Molten Gatekeeper

Every other creature you control that enters pings each opponent for one, which reframes what a go-wide board actually accomplishes. Aristocrat and token decks have long converted bodies into life loss through sacrifice; here the conversion happens at the point of entry, before anything dies. That shift stacks with itself: a single wave of tokens becomes a burst of reach damage that scales with how many creatures resolve at once, and survival never enters the equation. The unearth clause pushes it past a one-and-done payoff. Once it dies, one red mana buys it back with haste for a turn, so the pinger returns exactly when you are about to flood the board again, then exiles itself cleanly at end of turn. Making it an artifact creature with unearth rather than a spell keeps it in artifact-matters territory and grants a second life through graveyard recursion that a creature-typed enchantment engine could not offer. The 2/3 frame is deliberately unremarkable: it exists to shrug off a stray point of damage while the trigger does the real work, not to attack. What it represents is a compression of the classic damage-on-entry effect into a low-cost, recurring package, an engine piece that pays off decks generating bodies in bunches rather than ones forced to build around feeding it.