Most of why this effect is amazing on Clique is because of the already playable body. As it is we're spending 5 mana to (slightly?) lower the opponents overall card quality.
I've run bottled cloister before and it did do work (when it wasn't mind twisting it's owner when it got shattered, something this one avoids)
I'm adding one as soon as I get it. Wildfire Baby!
Notice the designer credit. I have a feeling some asshole was like "I want a black card with hexproof, first strike and deathtouch" and they were like "LOL HERE FUCKER"
Yeah I kinda err towards more grave-hating removal.
I'm currently doubling up on anger of the gods rather than Anger + slagstorm. Gravecrawler decks can get stupid
Slot that opposition into GW tokens :P
It wont always be an interesting synergy card though. I see a many generic aggro deck naming Geralf's Messenger tho