Cumulative upkeep (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
When Arctic Wolves enters the battlefield, draw a card.

Trample
Whenever Aurochs attacks, it gets +1/+0 until end of turn for each other attacking Aurochs.

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

Trample

Haste
When Lava Hounds enters the battlefield, it deals 4 damage to you.

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.

Enchant creature (Target a creature as you cast this. This card enters the battlefield attached to that creature.)
Enchanted creature has first strike. (It deals combat damage before creatures without first strike.)

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

When Rogue Elephant enters the battlefield, sacrifice it unless you sacrifice a Forest.

Menace (This creature can't be blocked except by two or more creatures.)

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

Rampage 2 (Whenever this creature becomes blocked, it gets +2/+2 until end of turn for each creature blocking it beyond the first.)