Estwald Shieldbasher

Four power on two toughness is a body that trades badly and blocks worse: two toughness dies to nearly anything, and the four power only matters if it connects. The optional attack tax answers exactly that fragility. Paying the extra mana on the swing turns the glass cannon into something that walks through blocks and ignores combat damage, and because the indestructible lasts until end of turn, it also shrugs off a sweeper or point-removal spell fired on your own turn after attackers are declared. What it does not do is protect the creature on defense: the trigger only fires on attack, so a sorcery-speed board wipe on the opponent's turn finds a plain two-toughness body with no shield up. That asymmetry is the whole tension. The protection is priced per swing rather than baked into the rate, so any turn you cannot spare the mana is a turn the creature reverts to a fragile liability. The soft toughness keeps it from being a wall, which keeps it pointed forward, and the mana sink gives a flooding aggressive deck something to do with a topdecked land. It is a small, well-behaved piece of design: a strong attacker that stays vulnerable until the moment you decide, on your own turn, that it isn't, and only while the mana holds out.