Omnath, Locus of God

Trample, Hexproof
Whenever an elemental enters the battlefield under your control, search your library for a land, put it on to the battlefield, then shuffle your library.
sacrifice 7 lands; target player gains 7 life, draw 7 cards, and puts a permanent with converted mana cost 7 or less onto the battlefield, then taps 7 permanents they control, they don't untap on their next untap step.