Gurney
While there's no set definition for what "gurney" as an insult actually means, it is generally acknowledged to be a bad thing, and in no case, under any circumstance should "gurney" be used in a positive way. The term "gurney" can be used as an adjective or a noun (whichever works for the situation).

(theres also the literal definition: a four-wheeled stretcher for transporting hospital patients from place to place ;a wheeled cart or wagon with canvas sides, used in post offices to route mail.)
"Shut your gurney face"

"Screw you, you fuckin' gurney"

"Your mom's a gurney"

"They had to carry him out on a gurney"