If you control "Toon World" and a Toon monster: Target 1 card in your opponent's Graveyard; if it is a monster, Special Summon it to your side of the field, or if it is a Spell/Trap Card, Set it to your side of the field. You can only activate 1 "Mimicat" per turn.
Huh, I just tried it again and it works. For some reason it didn't work one time when I had Toon Summoned Skull and Toon World, one open monster zone and spell/trap zone, and my opponent had plenty of monsters and spells in his graveyard.
The same problem here, in case of having only 1 open spell/trap zone; it sometimes only lets me take a monster card from opponent's graveyard but other times it works just fine. I thought I am not able to use it properly at first but it happened several times.
This card tilts Pheonix and REBD players pretty hard when I steal their monsters from the graveyard