The Cool Friends Gang are Denzel's group of former fellow gangsters from Detriot. Members are Murder Bone, Bug Eyes and the last one with the glasses whose name was never revealed.
They only appear in the Season 2 episode Scared Straight. They also disappear midway in the episode since Warden Tiny Smalls pardoned them off, but still kept Denzel in prison.
Denzel mentions them in Trip to Mars.