This effect goes off even if Zamazenta gets knocked out , making it a great option to have up front early in the game
The whole point of showcase frames is that they make opening booster packs more fun, but they weren't included in the already more expensive basic Double Masters boosters
The right play is going to depend on the matchup (if they're a very fast deck it could be right to block), your hand (if your next play is a Ghoulraiser and your creature is instead a Walking Corpse, it is excellent to block), and your tribe along with your deck
I see the power here, but in a game thats been power crept since Coldsnap (?!??), a 6-drop that opponents have to decide they let trigger seems like a terrible deal
Or, for more collectibles, here are the rare Pokmon cards worth chasing and the best Pokmon cards power-wise.