pokemon booster.box 151 Booster Box (Japanese) This set is headlined by Tera Ogerpon ex Pokemon Japanese Mask of Change

Yes, a four-mana activation cost is a lot, and only flipping into a nonlegendary creature means the ability isn't as strong as it could be, but the amount of times I've seen this flip into a Blightsteel ColossusBlightsteel Colossus is insane

Though realistically all of these do very little, it adds another layer of excitement and mythos to the TCG

It looks like a nice green creature for Commander and a sideboard or maindeck threat for Standard because some decks will have a hard time dealing with it

Chaos Number 40: Gimmick Puppet Of Dark Strings only lets the player draw a card upon destroying enemy monsters via effect, not battle too