Warthog

Swampwalk (This creature can’t be blocked as long as defending player controls a Swamp.)

Bull Elephant

When Bull Elephant enters, sacrifice it unless you return two Forests you control to their owner’s hand.

Pygmy Hippo

Whenever Pygmy Hippo attacks and isn’t blocked, you may have defending player activate a mana ability of each land they control and lose all unspent mana. If you do, Pygmy Hippo assigns no combat damage this turn and at the beginning of your next main phase this turn, you add an amount of equal to the amount of mana that player lost this way.

River Boa

Islandwalk (This creature can’t be blocked as long as defending player controls an Island.)
: Regenerate River Boa.

Bull Elephant

When Bull Elephant enters, sacrifice it unless you return two Forests you control to their owner’s hand.