Nice Art!
You should probably lower the cost though, since it doesn't actually kill the creature.
This can be worse, since it actually keeps the creature alive. You would have a 1|1 critter instead of an empty slot. Thus, with a shield (now in "other"), you could make it an unuseful slot...
Still UP, any actually powerful use, and Gravity's shield actually benefits from high hp...
GOTTA IDEA! What if this lowered atk and upped hp? Super synergy with grav-shield, and armagios too
Or you could maintain your idea and low the cost to... 4/3
?