How can you create a combo with Rootha, Mercurial Artist, Refuse // Cooperate?
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[START OF COMBO]This combo can be formed with Rootha, Mercurial Artist, Refuse // Cooperate

Color identity: UR
Mana cost: {4}{U}
Steps:
  1. Cast an instant or sorcery spell, or wait for an opponent to cast one.
  2. Holding priority, cast Cooperate from your graveyard by paying {2}{U}, targeting the spell.
  3. Activate Rootha by paying {2} and returning it to your hand, copying Cooperate, with the copy targeting the original Cooperate.
  4. Resolve the copy of Cooperate, copying Cooperate, targeting the original Cooperate.
  5. Repeat step 4.[END OF COMBO STEPS]

Result:
  - Infinite magecraft triggers[END OF COMBO RESULT][END OF COMBO]

Other prerequisites:
  - Rootha, Mercurial Artist must be on the battlefield
  - Refuse // Cooperate must be in the graveyard
[END OF COMBO PREREQUISITES]
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