Never mind that Brontosaurus didn’t actually exist (it was a conflation of a couple other species that did exist) I don’t know what the gag is. Or what the things on the rotisserie are.
The comments seem to confirm my guess, that the things on the spit are supposed to be Bronto-balls™. But I don’t get the joke either, beyond Beavis&Butthead-style humor?!
The essence of the joke here is good: that perhaps the pyramids had a second use in providing entertainment for Pharaoh. Not getting the extra graft part.
The joke here is also basically clear, with that nice added pun in the lefthand corner. But why a cat?
(a) To get in the way while he’s working, as cats tend to do?
(b) An allusion to the supposed origin story of Jim Davis developing Garfield? “Davis decided to peruse current comic strips to determine what species of animal characters might be more popular. He felt that dogs were doing well, but noticed no prominent cats. Davis figured he could create a cat star, having grown up on a farm with twenty-five cats.” (Wikipedia)
(c) An inside joke that cartoonists tend to be cat people?
Yes, yes! One of these guys sold me a “This is not a shirt” tee shirt.
…
Unless it was one of these guys! Number five looks very sus!
Boise Ed sent this one in, noting “The robotic lawn mower is just doing what it is supposed to do, right?”
Your editor, drawing from unfortunate personal experiences, sees allusions to the problems caused when one dog is on leash, but another dog is not, or maybe just barking dogs in general. So we’re marking this CIAU (Comic I almost understand)