Trample, islandwalk

As an additionnal cost to cast River King Giant, sacrifice an island and a forest.

Whenever a creature you control deals combat damage to an opponent, if you would draw a card, you may put two +1/+1 counters on River King Giant.

Whenever a creature you control attacks, you may remove a +1/+1 counter from a creature you control, if you do, until end of turn, when that creature deals damage to an opponent, you may draw a card.