I couldn't resist playing a joke on our old vet one day. I'd fixed some cellophane noodles for dinner and they're quite odd looking.
I decided they were VERY odd looking, so I bottled a little knot of them up in a small jar with some alcohol and just a touch of Worcesterhire (for color). I took them in to Dr. B the next morning, and with a straight - and very worried face told him one of the animals had passed them on the rug. He picked up the jar, looked and looked at it and pronounced that it looked like some type of worm, but had no alimentary canal. He asked one of his techs to make a slide with a piece of one and stuck it under the microscope. After he'd puzzled over it for about five minutes I couldn't stand it anymore and 'fessed up.
I thought he was going to fall off his stool laughing.
He kept the jar and pulled the same thing on another vet . . .