RedBelly are two bosses in Borderlands: The Pre-Sequel that appears in Crisis Scar. Red and Belly are 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 around 10-15% of their combined health is missing.
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.
The name RedBelly and the Black Snake SMG are also references to the Australian Snake, the Red-bellied black snake.
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."
Despite the Ned Kelly reference, Belly's critical hit location is his head while Red's crit location are his legs. This is made more fitting by the fact that Red comments that "nobody's gonna shoot you there."