rib splitter 

A rib splitter is a tool made and used in prison. It's a shank that is quickly thrusted into the ribs around the arm pit region deep enough to split the ribs and hopefully penetrate the lungs. This will deflate the lungs and ensure a quick effective shank.

Tony shanked levi with a rib splitter for not finishing him off.

rib splitter by youneek October 18, 2008

Rimsplitter 

A huge shit that makes you feel as though you'll be bleeding out through your ringpiece for weeks.

Dear God, that was one hell of a rimsplitter.

Rimsplitter by shoe face January 16, 2008