I just had a crazy idea. What if Alf was a guest star on Muppets Tonight if it was still on the air. The Muppets could sing "Consider yourself", just like they did for Edgar Burgan and Charlie Macarthy. And since he dishes out the wise cracks, he could heckle Seymour and Pepe when they do their comedy routine. Probably like this.
Pepe: Hey Seymour.
Seymour: Yes Pepe?
P: What do you get when you cross a chicken with a duck?
S: Gee, I don't know, what?
P: You get a hen that lays down!
[Rimshot, but no reaction from audience.
Alf: Hey! Your routine is like a rotten egg! It stinks! Ha! I kill me!
P: You shut up hairball!
A: Oh come on. It was a good "yolk"! HA! I kill me! Again!!
I can't think of any more examples, but I'll put them up if I think of them.