Circle of the Moon Druid

The archetypal bear body, split down the middle by whose turn it is. On your turn it becomes a 4/2, a genuine attacker that trades away two points of toughness for two points of power right when you want to swing; on everyone else's turn it settles back into the 2/4 wall that survives most early combat and shrugs off small burn. This is a flavor-first design (the Circle of the Moon subclass in the source material shapeshifts into a bear) that lands on a real green tension: the color wants blockers that also press tempo, and a single-mode body forces you to pick which. This one picks both, and the mode change rides the turn structure the game already tracks rather than an activated ability you have to pay for and remember. The wrinkle worth noting is the type-line swap. During your turn it becomes a Bear and loses every other creature type, so it stops being an Elf or a Druid for anything keyed to those tribes, then quietly regains them the moment your turn ends. That is a narrow window, but a real one for tribal payoffs and anthems that check for a type during your combat. What it settles into is a green three-drop that reads defensively on paper and hits offensively in practice, the offense and defense scheduled automatically by phase rather than paid for a second time.