Advanced Dungeons & Dragons: 1st Edition Fiend Folio (part 2)
Zack: There is no excuse for this thing.
Steve: What about 20 of this thing?
Zack: It just irritates me imagining running an encounter with Gorbels The DM has to sit there and write down 20 different beach balls with eye stalks that are going to ceaselessly try to jump on people's backs and bite them. For no apparent reason.
Steve: They're mischievous! And irritable!
Zack: They're also super fast, so they're going to catch you no matter what. And then you will get rewarded with Hitchhiker's Guide to Greyhawk here digging his little talons into your neck.
Steve: The good news is the Gorbel is immune to blunt weapons. The bad news is when you stab it with a sword it explodes and hurts you.
Zack: That's just what we need: exploding problems.