It looks a lot like SpongeBob, except he is giant, has razor teeth, and his shirt is torn. Instead of eyelashes, it appears to have a unibrow. There are two hair-like growths on each arm. Its eye color is red instead of blue and its eyes appear to be bloodshot. There are also dark outlines around the eyes. Its teeth are vampire-like and show pink gums when the mouth is open. The inside of the mouth, including the tongue, is purple and it has light lips. Its tie also appears to be slightly torn.
It is mostly angry. However, SpongeBob and Patrick calm it down with Krabby Patties. Liking this state of mind, Spongezilla proceeds to pick up the Krusty Krab and starts eating things inside of it. It also seems to be unreasonable. This could be due to the fact that he is a giant and cannot hear SpongeBob or possibly due to him being a nightmare character.
It terrorizes Bikini Bottom in a dream that SpongeBob has, including a break-in at the Krusty Krab.
Spongezilla is a reference to the fictional monster Godzilla.