whoop ass
   \`whoop 'ass\ n.

A dangerous substance, usually found packaged inside cans. When released, can cause major damage to the person it is intended for, and is often used as a weapon of destruction. More often the user warns the recipient of an imminent opening of a can, if the recipient does not act as desired by the opener.

"If you don't shut up I'm gonna open up a can of whoop ass!"

"If you go ahead with that plan, you're gonna see me open up a can of whoop ass on you!"

"Boy, we're gonna open up a whole case o whoop ass on your ass!"