RedBelly is a boss in Borderlands: The Pre-Sequel that appears in Crisis Scar. He is composed of two enemies, Red and Belly, a pair of Scav leaders. Red is a Lil' Scav wearing a full-sized helmet who sits atop Belly to appear as one figure. The two separate to attack individually after enough damage is dealt.
Belly's critical hit point is his head, while Red's critical hit point are his legs.
Red has a chance of dropping the unique SMG, Black Snake.
Sometimes, if Red is killed after Belly, Lil' Scavs will continue to spawn in RedBelly's Arena until Crisis Scar is exited.
The name RedBelly is a play on legendary Australian bushranger Ned Kelly. The two have a discussion in an ECHO recording about Belly's missing leg armor. This is a reference to how Ned Kelly was finally taken down: Two shotgun blasts to the knees.
An ECHO recorder found in the area implies that Red and Belly have been deputized by the Meriff, as they are now on "this side of the law."
Ironically, despite the Ned Kelly reference, Belly's critical hit point is not his legs, but his head - instead, Red is the one takes critical hits in the legs. This is made more fitting by the fact that Red comments that "nobody's gonna shoot you there."