Harbinger of the Dark Forest

Exile cards from the top of your library until you exile a basic Swamp or a basic Forest. Reveal that card and place all cards exiled this way into your library and shuffle it.
If a Swamp was revealed, Harbinger of the Dark Forest gains +0/+2 and Deathtouch.
If a Forest was revealed, Harbinger of the Dark Forest gains +2/+0 and Trample.