It's his underbite, with the way the lip comes to a point, the teeth sticking out, and the bug eyes. We think it was either a dog or a fish. Kyle, from Despicable Me, is pretty close, but has too many teeth and his mouth is too round - we also think it was 2d animation.
Overall, the character was more comic relief; we think it went around biting people a lot or something for comedic effect. No talking. Anybody have any ideas?