From publisher blurb:
Two great games that go great together - Toon and Munchkin! All the crazy characters, silly spells, troublesome traps, mirthful monsters, wondrous weapons, and terrific treasures from the Munchkin card game are now yours to play in Toon, the funnest roleplaying game ever.
The whole idea behind the Munchkin card game is to venture into dark dungeons, slay monsters, take their stuff and then, when the time is right, slay your fellow munchkins and take their stuff. As you may have noticed, this sounds suspiciously like not only a session of Dungeons and Toons, but most other fantasy roleplaying games. The big difference is that Munchkin and Dungeons and Toons reward such behavior, while other roleplaying games tell you it's a bad thing.
Please note that Toon Munchkin is not a complete game. You will need the basic Toon rules and the Dungeons and Toons rules from the Tooniversal Tour Guide to play.