An intrusion is an igneous rock body that forms from crystallized magma under Earth's surface.any mountain ranges, such as the Sierra Nevada in California, are formed mostly by intrusive rock, large granite (or related rock) formations. Intrusions are one of the two ways igneous rock can form; the other is extrusive, that is, a volcanic eruption or similar event.
Admit it: you were pronouncing the word âSmaugâ â the name of the Hobbit dragon, the one whoâs in the subtitle of the upcoming movie installation â as âsmog.â.
For the lizard genus named after the character, see Smaug (genus) . Smaug (/smaÊÉ¡/) is a fictional dragon and the main antagonist in J. R. R. Tolkien 's 1937 novel The Hobbit. He was a fearsome dragon who invaded the Dwarf kingdom of Erebor 150 years prior to the events described in the novel. In The Hobbit: The Battle of the Five Armies, Smaug attacks Lake-town. 2  He is killed by Bard with an elongated iron arrow as his body falls on the boat carrying the fleeing Master of Lake-town. 3  It is later revealed that Smaug's attack on Erebor was all part of Sauron's design.