Guess I'm similar to, gangrene when I'm, angry then I'm

from Slaughterhouse (Ft. Eminem & Skylar) – Our House Lyrics on Rap Genius

This is referring to the previous line where he is “bad to the bone” at rap. Gangrene is a disease where tissue dies and could lead to amputation, so he’s metaphorically (for litteral “good at”) bad/rotten to the bone to a point needing amputation.

Gangrene causes the skin to decay and become blackish-yellow/green in color. Sets up next reference, since Bruce Banner only transforms into Hulk when he’s angry and becomes a green behemoth.

To help improve the meaning of these lyrics, visit "Our House" by Slaughterhouse (Ft. Eminem & Skylar) Lyrics and leave a comment on the lyrics box