Second Sunrise

The symmetry clause is the disguise: returning every player's artifacts, creatures, enchantments, and lands that hit the graveyard from the battlefield this turn reads as even-handed, until you notice the deck casting it has rigged the turn so only its own things hit the graveyard. What it actually is, is a reset button for sacrifice value. Anything that sacrificed itself or got destroyed this turn returns, and every "enters the battlefield" trigger fires again on the way back. That recursion-plus-retrigger loop is the entire reason the card lives in infamy rather than the bulk bin.

The danger is what happens when the cost of recasting it drops to nothing. Pair Second Sunrise with a critical mass of zero-cost artifacts and a sacrifice-driven mana source like Lotus Bloom, and each cast becomes net-positive: sacrifice the board for value, raise the sun, repeat. The loop is deterministic, but it is also methodical to the point of cruelty, every iteration re-resolving a stack of triggers, and that grinding pace is exactly what turned the engine into a competitive-play hazard once players assembled it. The flavor (a second dawn undoing the day's deaths) is unusually literal for a card whose real function is to make a sacrifice engine repeatable until something in the chain breaks. Plenty of cards reward building around them; this one rewards building a machine that no longer needs you to think.