Frilled Sea Serpent

A 4/6 for six mana is a defensive rate first: a body that trades up against most attackers and stonewalls the ground once the board fills out. What keeps the serpent from being purely reactive is the escape hatch bolted onto it, an evasion clause meant to turn a static advantage into a clock. The problem is the arithmetic. Making it unblockable costs seven mana in a single turn, which means the four power only pushes through in a game that has already gone long enough for that mana to exist with nothing better to spend it on. This is the classic blue mana-sink wall: a durable blocker with a late-game finisher grafted to the side, so that a stalled board is not a dead end. The defensive role is the real job; the unblockable line is what you reach for after the game has ground to a standstill and you need a way to convert a lead into damage. It is a design pattern as old as blue itself, the patient control finisher that spends the game holding the fort and then, in the turns where mana outstrips options, quietly turns the corner. The rate never impresses on its own; what it offers is a floor (a wall that holds) and a ceiling (an unblockable clock) with a wide, mana-hungry gap between them.