Thanks very much, Priestess of Syrinx!!! That pretty much explains everything! So it is an anime
("Yokaizer is a Japanse anime like Pikachu etc.") and the characters are referred to also as "Ghost Kids." What's confusing me and really piqued my interest is that they say it reacts to microwaves, "like the Tamagotchi Wave UFO!?" I didn't know there were ANY virtual pets that reacted to microwaves! I have no clue what that means or how it works...I guess I'm gonna have to do some experimenting. Wow!
how did you search for it on ebay?
The auction itself was called "Tamagotchi Tamagotch Toy Friend Cyber Pet Game" I think I had simply searched for "tamagotch," since leaving off the "i" usually returns results of Japan-only stuff rather than tons and tons of American units.
I KNOW I saw another one as Buy-It-Now for $11.99, and I was gonna put the link to it here in case anyone else was interested in getting one, but when I went back to get the link, for the life of me I cannot find it! Possibly in the few hours in between when I saw it and now, someone DID buy it now, and it's simply gone.

If I come across another one, I'll post the link. Interestingly, the plastic of the one I bought looks like it glows in the dark; I sure hope that's the case! I LOVE stuff that glows in the dark!
