2020-01-24 : Dreamshaper Shaman can be sacrificed to pay for the cost of its own triggered ability.

2020-01-24 : If there are no nonland cards remaining in your library, you just randomize your library and continue playing.

2020-01-24 : While resolving Dreamshaper Shaman’s ability, you can’t pay {2}{R} more than once or sacrifice multiple permanents.

2020-01-24 : You can’t pay {2}{R} and not sacrifice a nonland permanent, or vice versa. The cost must be paid in full or not at all.