Both Spooky and Ariel are enjoying their Christmas present immensely. It's a mechanical-type Tamagochi called "Mutsu the Curious Fish" by Tiger Electronics. You fill this tank with an inch of water, then place a tiny plastic fish in the tank. There are 3 buttons to feed the fish, and a motorized magnet under the tank pulls the fish around to make it seem alive. It also has a microphone so it responds to sounds, and a speaker to play back the typically bizarre Japanese "oooooh" and "wheeeeeeooooh" and "squeeeeeik" electronic animal sounds.

Mustsu is inedible, never dies, and always swimming around within paw-reach for some batting around. The *perfect* prey. :)