If your opponent targets an MTG Ward creature with an ability or spell, that spell or ability is immediately countered, unless they pay the Ward cost
While some monsters can be naturally special summoned under certain conditions, these are generally summons made by card effects
Its activated ability then ensures it wont only be seen as an early game card, as for an admittedly expensive six mana activation, it becomes a 5/5 Flying, Lifelink creature for the turn, putting it close to Baneslayer Angel territory in terms of usefulness
We have the all-important themed Sol Ring, and Generous Gift sees wide-spread EDH play, but the set lacks chase rares like the Hammer
Since Terra doesnt bring the reanimated creature back tapped and attacking, its a fundamentally less aggressive commander, but the lower mana cost to reanimate the creature gives you more flexibility on the turns you use the ability
Good luck removing it