Glacier Godmaw

Most landfall creatures ask you to build a deck that can trigger them; this one arrives with its own fuel attached. The Lander token it makes is a stored land drop, a trigger you can cash in on your own schedule rather than one you have to hope the top of your library provides. That converts the landfall clause from a passive incentive into something you can point at a specific attack step. The overrun it hands out (+1/+1 across the board plus vigilance and haste until end of turn) reads like a one-turn Craterhoof Behemoth splinter stapled to a body big enough to matter on its own. Vigilance carries more weight than it looks: it lets the whole team swing while still holding back a defensive wall against the crackback, so the alpha strike does not leave you exposed. Haste answers the seven-mana problem directly, since anything already on the battlefield when the trigger fires arrives ready to attack. The Lander guarantees you can pop the anthem the turn it lands if the mana is up, and any other land entering (a fetch-style effect, a bounce-land returning, a second drop off ramp) fires it again for free. It is a finisher built to close the same turn it stops being just a 6/6 with trample, and it counts on green's habit of flooding more than one land into play per turn to keep the anthem going.