Character: giant rat (jerma985)
The titular Rat, and partial antagonist, from the YouTube video Rat Movie: Mystery of the Mayan Treasure by Jerma985.
Commonly associated with the phrases: "I'm the giant rat that makes all of the rules," and "Let's see what kind of trouble we can get ourselves into."
The specific model used for the Giant Rat (and by extension, the other rats) is labelled "Fabrice the Rat," and has been ported to various platforms, following the widespread success of Rat Movie and its sequel.