Reigol, The Primordial Cold

Freeze
Unfreeze — sacrifice 4 frozen permanents.
Whenever Reigol deals combat damage, you may sacrifice frozen permanent. If you do, search in your library for a permanent card and put it onto the battlefield, then shuffle.
At the beginning of your upkeep, if Reigol frozen, create a 5/5 Beast creature token with Freeze, Trample and "Unfreeze — {5}{u}{u}".