Teenagers from Outer Space (1997)

From the back of the book.

EEK! EEK! YATTA! YATTA! EEK! EEK!

Tommy Tanaka dove under his desk as the Disco Dwarves from Dimension X teleported with a "pop" into his Homeroom. Zap rays sizzled overhead, vaporizing his English is Fun textbook and scorching one of the slower freshmen nearby. There was a sound like tearing rubber as, int he corner, Vilar Monstered Out to his full thirteen feet-twop and began throwing desks around. Cano started to shapechange, but a stray Boy/Girl gun turned him into a cute blonde Cannete.

Rami cringed behind her desk, her saucer-sized eyes wide with mindless terror (actually, everything about Rami was mindless), the tip of her long fluffy tail stuffed into her mouth. "What do we do now?" she wailed at Tammy. "No problem," said Kev, pulling the pin on his Weird Science 101 project and lofting it casually towards the Dwarves. There was a thunderous paisley explosion and the room was suddenly filled with hot buttered popcorn...

Welcome to the world of Teenagers from Outer Space: the amazingly weird roleplaying game that lets you become a character in your own (or even somebody else's) Japanese Animation Comedy Show! Complete with everything you'll need to create Silly Superpowers, Gonzo Gadgets, Bikini Battlesuits, Mecha Mayhem, Magical Girlfriends, and the ever popular sex changing Boy/Girl Gun, this new edition of the original award winning game is guaranteed to change the way you look at anime (and roleplaying) forever!