Screaming Nemesis

The trap is baked into the rules text: this is a red creature that punishes you for interacting with it, and the punishment scales with your commitment. Point a burn spell at it and the damage bounces back at a target of the controller's choosing. Block it and it deals that much damage right back to another target. Every removal decision becomes a two-part question: can you kill it, and can you afford where the leftover damage lands? That alone would make it a nuisance, but the lifegain lockout is the part that reshapes matchups. Any player dealt damage this way is locked out of gaining life permanently, which turns a redirected point of burn into a standing tax on the decks that survive by climbing back up: soul-sisters engines, incidental lifelink, fog-and-stabilize control shells. The design is doing two jobs at once. As a body it is a 3/3 with haste that demands an answer; as a hate piece it is a lifegain shutoff you can staple onto an aggressive curve without spending a dedicated slot. Red has long had ways to punish lifegain (Sulfuric Vortex, Rampaging Ferocidon), but those asked you to run a card that did only that. Here the effect rides on a creature you already wanted to attack with, and it triggers off the opponent's own removal, which is what makes it awkward to play against rather than merely annoying.