Sluggo
Sluggo was a lifeform resembling the Earth slug. Sluggo was selected by Ensign Hoshi Sato of the Earth starship  to be a souvenir from a visit to a planet which had an argon rich atmosphere. In 2151, after Enterprises maiden voyage, Sluggo was the only alien contact the crew had encountered, much to the chagrin of Commander Tucker.

Once aboard Enterprise, Sluggo had a difficult time adjusting to the new environment and as a result would not eat. The Enterprise doctor, Phlox, attempted to use an argon lamp to recreate its native habitat. He also attempted to coax the creature into eating using a protein concentrate, but to no avail. Phlox suggested that it be fed to his Pyrithian bat instead of having Captain Jonathan Archer go out of the way to find a new home for it. Sluggo was transplanted onto a planet similar to its own on May 6th, 2151. 

Sluggo had the distinction of being the first official first contact with a previously unknown alien species by the Enterprise. ()

de:Schneckchen
Slugs