Seven mana for a 12/12 trampler is already a decent starting point, but the real value of this card lies in the flexibility of its on-attack trigger. Being given the option to make a huge, attacking monster or a bunch of small, lifelinking chump blockers means that no matter the board state, no matter if you’re ahead or behind, you’ll be able to get excellent value from Ghalta and Mavren. Best of all, it doesn’t just trigger when it attacks: you can play this card, attack with one of your other Dinosaurs, and immediately cash in by creating tokens.