Snitch definitly wasn't the best idea I had...But my thought was that the Snitch would slam the creature out the field to the player's hand or something, I also was trying to create a more 'original' creature that was still thematically appropriate...
I vote again for a crossover between a Snitch and a Pokèball! And the bounce ability would be renamed "capture"!
(see attachment!)
Talking seriously, we should think of a fictional creature, even inspired on the snitch, that have the ability of catch/unsummon/whatever other creatures.
Something like a flying egg, that is capable of "unbirthing" creatures? That's so
...