# Troll
Trolls are a class of monsters in NetHack. They are notable because the corpses of dead trolls will revive (similar to the Riders). For that reason, trolls are one of the more annoying monsters. Trolls can also make use of polearms—they can pound with one at the same range as a character who is Skilled in polearms. They have a 50% chance of being generated with one of a ranseur, partisan, glaive, or spetum.[1]
A troll, T, is also the least powerful monster of this class. Other types of troll include ice trolls, rock trolls, water trolls, and Olog-hai.
Players polymorphed into trolls should be careful around cockatrices; attempting to attack a cockatrice in troll form will cause you to bite it and turn to stone.

Contents

1 Revival
2 Strategy

2.1 As pets

3 Messages
4 Individual information

4.1 Troll
4.2 Ice troll
4.3 Rock troll
4.4 Water troll
4.5 Olog-hai

5 Mythology
6 Encyclopedia entry

6.1 Troll
6.2 Water troll
6.3 Olog-hai

7 Variants

7.1 UnNetHack

8 References

Revival
When a troll is killed, its revival timer is set such that it has a 1⁄37 chance of reviving per turn, starting 2 turns after death, but not more than 50 turns after death.[2] This results in an approximately 74% chance that a troll will revive within 50 turns. Wielding Trollsbane when a troll attempts to revive will prevent it from doing so.[3] If a troll corpse is unable to revive when the revival timer expires, it will begin to rot, and will not revive at all.[4]

The following information pertains to an upcoming version (NetHack 3.7.0). If this version is now released, please verify that it is still accurate, then update the page to incorporate this information.

Trollsbane prevents the revival of trolls killed by it, instead of all troll corpses that attempt to revive while it is wielded. (commit 328dc5bd)
Strategy
Generally speaking, for well armed characters, trolls do not pose a major threat, but preventing them from reviving can be tricky. There are a large number of ways to kill a troll permanently, many of which involve putting the corpse inside something:

Eat the corpse. It will disappear only when you are finished. During the meal, it may revive, or you may be interrupted, or you may become unconscious from rotten food. This is a readily available option as long as you are not satiated.
Let a pet eat the corpse. It will disappear as soon as the pet starts to eat, though this option is only available if you have a carnivorous pet.
Tin the corpse. This is the easiest option for those with a tinning kit.
Lock the corpse in a container. Useful for trolls generated in throne rooms, though they may revive while being carried to their destination. Nesting a container more than 2 levels deep will also prevent reviving, as will a bag of holding 97.5% of the time.[5] You will receive the message "You feel less hassled" when a troll corpse stored in a container fails to revive.[6]
Just keep killing the troll. Each time you do, there is approximately a 25% chance that it will not revive.
Place the corpse in an ice box. The revival countdown will be paused. You can take it out later when you're ready to deal with it.
Stone the living troll with a cockatrice corpse. If there is a live cockatrice nearby, conflict can also (sometimes) induce the cockatrice to stone the troll.
Polymorph the corpse.
Throw the corpse into lava or water (if it isn't a water troll), and it will drown as soon as it revives.
Sacrifice the corpse.
Polymorph the troll and kill the creature. Make sure you're prepared in case the troll polymorphs to something like a master lich.
Find or dig a pit, place the corpse in, and push in a boulder to bury it. Water can also be used in the place of a pit (90% chance if the troll in question is a water troll).
Lure the troll to the Rogue level, where monsters don't leave corpses, and kill it there.
Crush the troll with a drawbridge.
Disintegrate the troll by standing between it and a black dragon, or just polymorph into a black dragon and fire a disintegration ray at it.
Digest the troll.
Turn the troll to slime.
Genocide trolls.
Put the corpse in a cursed bag of holding and repeatedly #loot the bag until it disappears.
Completely fill the level with monsters so that the troll has nowhere to revive.
Destroy the container with the corpse in it: a magical explosion for bags of holding, or polymorph for any container.  Probably not worth wasting a container, though.
Leave the corpse near a gelatinous cube. Cubes will readily eat corpses, with no regard to hunger, whether they are hostile, peaceful, or pets.

The following information pertains to an upcoming version (NetHack 3.7.0). If this version is now released, please verify that it is still accurate, then update the page to incorporate this information.

Cancelling a troll or its corpse will prevent it from reviving. (commit)
As pets
While not as strong as some other tamable creatures, higher-level trolls are still reasonably strong, can make use of some weapons, and can auto-revive when killed. Even though they do not always revive tame, the chance is small for them to revive hostile as long as you do not abuse them or kill them yourself. While they are not exactly so powerful that they're worth going out of your way to tame, a tame troll may still be worth keeping.

Messages
The 

<troll> rises from the dead!
A troll revived, and you could see it.
The bite-covered <troll> rises from the dead!
A troll revived from a partly eaten corpse (possibly while you were eating it), and you could see it.
Individual information
Troll

T troll 

Difficulty

9

Attacks

Weapon 4d2, claw 4d2, bite 2d6

T troll 

Difficulty

9

Attacks

Weapon 4d2, claw 4d2, bite 2d6

Base level

7

Base experience

97

Speed

12

Base AC

4

Base MR

0

Alignment

−3 (chaotic)

Frequency (by normal means)

2 (Quite rare)

Genocidable

Yes

Weight

800

Nutritional value

350

Size

Large

Resistances

None

Resistances conveyed

None

A troll:

 has a head, a couple of arms, and a torso.

 regenerates HP quickly.

 is carnivorous.

 is normally generated hostile.

 can follow you to other levels.

 is strong.

 has infravision.
 can be seen through infravision.

Reference

monst.c#line1798

Ordinary trolls are the weakest monsters in the troll monster class. They have no special abilities beyond reviving themselves, and they are often generated in throne rooms.

Ice troll

T ice troll 

Difficulty

12

Attacks

Weapon 2d6, claw 2d6 cold, bite 2d6

T ice troll 

Difficulty

12

Attacks

Weapon 2d6, claw 2d6 cold, bite 2d6

Base level

9

Base experience

205

Speed

10

Base AC

2

Base MR

20

Alignment

−3 (chaotic)

Frequency (by normal means)

1 (Very rare)

Genocidable

Yes

Weight

1000

Nutritional value

300

Size

Large

Resistances

Cold

Resistances conveyed

Cold (60%)

An ice troll:

 has a head, a couple of arms, and a torso.

 regenerates HP quickly.

 is carnivorous.

 is normally generated hostile.

 can follow you to other levels.

 is strong.

 has infravision.
 can be seen through infravision.

Reference

monst.c, line 1805

Ice trolls are immune to cold, and one of their attacks deals cold damage. They hit slightly harder than regular trolls if the cold attack isn't resisted. They have a slightly lower AC and some MR.

Rock troll

T rock troll 

Difficulty

12

Attacks

Weapon 3d6, claw 2d8, bite 2d6

T rock troll 

Difficulty

12

Attacks

Weapon 3d6, claw 2d8, bite 2d6

Base level

9

Base experience

198

Speed

12

Base AC

0

Base MR

0

Alignment

−3 (chaotic)

Frequency (by normal means)

1 (Very rare)

Genocidable

Yes

Weight

1200

Nutritional value

300

Size

Large

Resistances

None

Resistances conveyed

None

A rock troll:

 has a head, a couple of arms, and a torso.

 regenerates HP quickly.

 is carnivorous.

 is normally generated hostile.

 can follow you to other levels.

 is strong.

 can pick up weapons and food.

 has infravision.
 can be seen through infravision.

Reference

monst.c, line 1812

Rock trolls are basically more powerful versions of ordinary trolls. They hit slightly harder than trolls and ice trolls, but have no remarkable attribute otherwise besides reviving themselves. They have lower AC than ice trolls, but no MR.
In Dungeons &amp; Dragons, they are described as trolls with an affinity for earth that possess natural camouflage in areas of stone.

Water troll

T water troll 

Difficulty

13

Attacks

Weapon 2d8, claw 2d8, bite 2d6

T water troll 

Difficulty

13

Attacks

Weapon 2d8, claw 2d8, bite 2d6

Base level

11

Base experience

246

Speed

14

Base AC

4

Base MR

40

Alignment

−3 (chaotic)

Frequency (by normal means)

0 (Not randomly generated)

Genocidable

Yes

Weight

1200

Nutritional value

350

Size

Large

Resistances

None

Resistances conveyed

None

A water troll:

 can swim.

 has a head, a couple of arms, and a torso.

 regenerates HP quickly.

 is carnivorous.

 is normally generated hostile.

 can follow you to other levels.

 is strong.

 has infravision.
 can be seen through infravision.

Reference

monst.c, line 1819

Water trolls have higher MR than other trolls, but their AC is only on par with regular trolls. They don't hit as hard as rock trolls, but they can swim, so dumping their corpse in water isn't effective at getting rid of them.
Water trolls are not randomly generated; the only natural water trolls in the game are two of them that appear in one version of Medusa's Island.

Olog-hai

T Olog-hai 

Difficulty

16

Attacks

Weapon 3d6, claw 2d8, bite 2d6

T Olog-hai 

Difficulty

16

Attacks

Weapon 3d6, claw 2d8, bite 2d6

Base level

13

Base experience

325

Speed

12

Base AC

−4

Base MR

0

Alignment

−7 (chaotic)

Frequency (by normal means)

1 (Very rare)

Genocidable

Yes

Weight

1500

Nutritional value

400

Size

Large

Resistances

None

Resistances conveyed

None

Olog-hai:

 has a head, a couple of arms, and a torso.

 regenerates HP quickly.

 is carnivorous.

 is normally generated hostile.

 can follow you to other levels.

 is strong.

 can pick up weapons and food.

 has infravision.
 can be seen through infravision.

Reference

monst.c, line 1826

Olog-hai are the most powerful type of trolls, having lower AC than all other trolls (but no MR), and they hit as hard as rock trolls. They have no special attributes beyond reviving themselves.
The name is derived from J.R.R Tolkien's works, in which the Olog-hai were a species of trolls that served the Witch-King while he ruled in Angmar. Olog-hai did not turn to stone in sunlight as other trolls did.

Mythology
Trolls originate from from Scandinavian folklore. NetHack's depiction of trolls is more directly based on Dungeons &amp; Dragons. 
In the folklore, a troll is typically large, very strong, and dim-witted. It fears light or is turned to stone by it. Trolls in D&amp;D have regenerative abilities.

Encyclopedia entry
Troll

The troll shambled closer.  He was perhaps eight feet tall,
perhaps more.  His forward stoop, with arms dangling past
thick claw-footed legs to the ground, made it hard to tell.
The hairless green skin moved upon his body.  His head was a
gash of a mouth, a yard-long nose, and two eyes which drank
the feeble torchlight and never gave back a gleam.
[...]
Like a huge green spider, the troll's severed hand ran on its
fingers.  Across the mounded floor, up onto a log with one
taloned forefinger to hook it over the bark, down again it
&nbsp;scrambled, until it found the cut wrist.  And there it grew
fast.  The troll's smashed head seethed and knit together.
He clambered back on his feet and grinned at them.  The
waning faggot cast red light over his fangs.

[ Three Hearts and Three Lions, by Poul Anderson ] 

Water troll

It wasn't that the troll was _horrifying_. Instead of the
rotting, betentacled monstrosity he had been expecting
Rincewind found himself looking at a rather squat but not
particularly ugly old man who would quite easily have passed
for normal on any city street, always provided that other
people on the street were used to seeing old men who were
apparently composed of water and very little else. It was as
if the ocean had decided to create life without going through
all that tedious business of evolution, and had simply formed
a part of itself into a biped and sent it walking squishily up
the beach. The troll was a pleasant translucent blue color.
As Rincewind stared a small shoal of silver fish flashed
across its chest.

[ The Colour of Magic, by Terry Pratchett ] 

Olog-hai

But at the end of the Third Age a troll-race not before seen
appeared in southern Mirkwood and in the mountain borders of
Mordor.  Olog-hai they were called in the Black Speech.  That
Sauron bred them none doubted, though from what stock was not
known.  Some held that they were not Trolls but giant Orcs;
but the Olog-hai were in fashion of body and mind quite unlike
even the largest of Orc-kind, whom they far surpassed in size
and power.  Trolls they were, but filled with the evil will
of their master:  a fell race, strong, agile, fierce and
cunning, but harder than stone.  Unlike the older race of the
Twilight they could endure the Sun....  They spoke little,
and the only tongue they knew was the Black Speech of Barad-dur.

[ The Return of the King, by J.R.R. Tolkien ] 

Variants
UnNetHack
In UnNetHack, if you genocide trolls, you get a YAFM:

*plonk* (for actual genocide)
S3n7 1n s0m3 7r0llz!!! (for reverse genocide)
References

↑ src/makemon.c in NetHack 3.6.1, line 442

↑ src/mkobj.c in NetHack 3.6.7, line 1184-L1219

↑ src/zap.c in NetHack 3.6.7, line 788

↑ src/do.c in NetHack 3.6.7, line 1896

↑ src/zap.c in NetHack 3.6.1, line 729

↑ src/do.c in NetHack 3.6.1, line 1779

This page may need to be updated for the current version of NetHack.
It may contain text specific to NetHack 3.6.1. Information on this page may be out of date.
Editors: After reviewing this page and making necessary edits, please change the {{nethack-361}} tag to the current version's tag or {{noversion}} as appropriate.

</troll></troll>