Moraug, Fury of Akoum [Zendikar Rising Prerelease Promos] BT16-097 Weathered Sentinels can attack players

Weathered Sentinels can attack players who attacked you during their last turn as though it didn't have defender

You can only activate 1 "Magical Spring" per turn

When you cycle Rampaging War Mammoth

you'll find:

Moraug, Fury of Akoum [Zendikar Rising Prerelease Promos] BT16-097 Weathered Sentinels can attack playersSet: Zendikar Rising Prerelease Promos Type: Legendary Creature Minotaur Warrior Rarity: Mythic Cost: {4}{R}{R} Each creature you control gets +1 +0 for each time it has attacked this turn. Landfall Whenever a land enters the battlefield under your control, if it's your main phase, there's an additional combat phase after this phase. At the beginning of that combat, untap all creatures you control.