VIDEOS:
Talking Speleothems
The stalagmite with a toothache sketch in an episode of The Muppet Show ends with it and the others being inside the mouth of another stalagmite, which complains of its own toothache.
Example of:
Recursive Reality
Germ Enlarger
Example of:
Mega-Microbes
Muppets & Contract With Devil
Example of:
Deal with the Devil
Sam and Alice Cooper
Example of:
Insult Backfire