This elegant three-card loop creates a perpetual motion machine of card draw and lifegain once you trigger it with any initial life gain. Cleric Class acts as the engine's catalyst, converting life gain into a +1/+1 counter on Fathom Mage, whose own evolve-adjacent text immediately rewards that counter by making you draw a card. That drawn card feeds directly into Horizon Chimera, which catches the draw to trigger a fresh burst of life—magnified thanks to Cleric Class's replacement effect—which immediately loops back to place another counter on Fathom Mage.