Eddymurk Crab

The seven-mana printed cost is a fiction you're never meant to pay. This is a cost-reduction payoff dressed as a fatty: every instant and sorcery in your graveyard shaves a generic off the tab, so in a deck that has been trading cheap spells all game it lands as a 5/5 flash body for a couple of mana, sometimes less. The design leans on your bin rather than your hand: nothing needs to be held or resolved first, and a discipline of cheap interaction fills the graveyard as a byproduct of playing the game. The enters-tapped clause draws the honest line around the flash. On anyone else's turn it comes down tapped, so it cannot ambush as a surprise blocker and cannot swing back until the following turn; even on your own turn it has summoning sickness and won't attack until you untap. The body is a threat for later; the immediate value is the entry trigger. Flashed in during your opponent's beginning-of-combat step, before attackers are declared, its tap on two would-be attackers functions as a two-body pseudo-Fog; cast on your own turn ahead of an alpha strike, it clears two blockers for the rest of your board. That tap is instant-speed tempo bolted onto a body a control or tempo shell was already going to cast for a song.