For just two mana, Underworld Breach is so powerful, its problematic
Blitzball Shot will probably be just fine, but if aggressive green decks are any good, this will be one of the reasons
(It won't transform, though.) (6/6/2025) If this card somehow enters the battlefield with its back face up, it didn't transform, so you won't get an emblem
Pinnacle Emissary Artifact and affinity decks in Legacy and Modern have adapted Pinnacle Emissary as a powerhouse threat that fills the board with tokens faster than your opponents can keep up with it, and all for 1 mana thanks to warp
The former lets you search your deck for the other two, and gets a boost to its attack for each other attacking creature
It showed up in numerous decks as a card selection engine, resource generator through its attacking token, and created a threat that could cause serious problems unless it was killed