Bond Of Many Shapes

Elementals in your library, hand, and graveyard
have the "Changeling" ability. (This card is every creature types at all times)
Whenever an island enters the battlefield under
your control, create a 2/2 green elemental with
haste. Exile it at the end of turn.
Whenever a forest enters the battlefield under
your control, elementals you control gain +2/+2
until end of turn.