Another, possible thing, would be to make it so that it doesn't 100% of the time always effect a creature. We've seen this before and you know who I'm talking about, Thorn Carapace. >:[
Instead you could give it a 70% chance to deal 1 damage to the creature, as well as block one damage. This way it would be neither OP or UP maybe.
Just, uh, yeah, putting my thoughts out there.