Magar by paying ({1} magic symbol) ({R} magic symbol) ({B} magic symbol) , noting
Rise of the Eldrazi and putting it face down on the battlefield as a 3/3 creature.
During your next turn, deal combat damage to an opponent using the 3/3 creature that has
Rise of the Eldrazi noted.
The creature triggers, casting a copy of
Rise of the Eldrazi without paying its mana cost.
Resolve the
Rise of the Eldrazi copy, causing you to take an extra turn after this one.
Repeat from step 3 during each turn.
Notes
The discard outlet is provided as a method of getting
Rise of the Eldrazi into your graveyard, as it does not go to the graveyard after resolution. You can substitute any other method for this, including using mill or other techniques.