Wall of Lava

Red almost never gets walls, and when it does the design instinct is to make them do something walls aren't supposed to do: turn defense into offense. The repeatable pump is the tell. A 1/3 with Defender that can grow as large as your red mana allows is a blocker that eats almost anything in combat, but the firewall framing has a sharper use than survival. The pump is a mana sink, and a mana sink in red usually signals that the body is meant to be redirected: the real payoff has always been pairing the growing toughness or power with an effect that converts those stats into direct damage, or with a way to let it attack despite the Defender clause. On its own it stonewalls early aggression and dares the opponent to overcommit into a blocker whose size is capped only by how much red mana you can spend in a combat step. The lineage of red defenders that double as scaling bodies runs through plenty of later "Defender plus pump" experiments, but the core idea (a wall that grows rather than sits) was already fully formed here. It is a clean expression of red's relationship with walls: red doesn't build fortifications, it builds something that can be set on fire and pointed at the enemy.