An almost example from the DCAU:
In the finale to Justice League Unlimited and the DCAU as a whole, "Destroyer", Darkseid immobilises Superman with the "Agony Matrix" and pulls out the hilt of what is either a retractable knife with kryptonite blade or a lightsaber toasting knife. (See: Hitchhiker's Guide, Futurama, etc. :P)
He threatens to carve out Superman's heart but is interrupted by Lex Luthor before he can.
The blade is never explicitly identified as being made of kryptonite, nor is Superman actually stabbed... So what I'm saying is that this is a terrible answer. However, it's green and glowy, and made to kill Superman, so you figure it out.