The Grim Adventures of Billy and Mandy Wiki
The Grim Adventures of Billy and Mandy Wiki

Ernie is a space-crab who is a scientist and making formulas. He is one of the members of Underfist. He was a red crab with a TNT in his mouth like a cigarete. Fred Fredburger made a drawing of Ernie which shows he is blue and purple, instead.

Overview

It looks like Ernie was going to be part of the Underfist if he actually came in the series.