User blog comment:Thornlu/The Creature From The Title Sequeance/@comment-2222836-20120730172801/@comment-97.92.63.8-20120731171418

This creature has yellow skin, glowing red eyes, short legs, claws, and a large mouth filled with razor sharp teeth.

According to Dipper in the "Creature in the Closet" preview for Gravity Falls; it took a bite of his sock, crawled up the wall, drooled purple slime, and hid in closet for 6 hours.

A better picture of the "closet creature" was on Dipper's postcard to his parents. The creature supposedly took a bite out of the picture. It could also be creature #26 in Journal 3 since Dipper labled the picture "THING #26".

http://gravityfalls.wikia.com/wiki/File:Gravitycard_02.jpg