Saijen, Naturalist-Sage

When Saijen enters the battlefield, exile all lands
you control.
Whenever you cast a noncreature spell, you may
search your library for a basic Forest card and
exile it. Then shuffle your library.
When Saijen leaves the battlefield, put all lands
exiled with Saijen onto the battlefield. They
become 3/3 green Elemental creatures with
trample.