How can you create a combo with Liliana, Untouched by Death, Rooftop Storm, Ratadrabik of Urborg, Necroduality?
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[START OF COMBO]This combo can be formed with Liliana, Untouched by Death, Rooftop Storm, Ratadrabik of Urborg, Necroduality

Color identity: WUB
Mana cost: 
Steps:
  1. Activate Liliana's third ability by removing three loyalty counters from it, allowing you to cast Zombie spells from your graveyard this turn.
  2. Cast Ratadrabik either from your hand or from your graveyard by paying {0}.
  3. Ratadrabik enters the battlefield, triggering Necroduality, creating a token copy of Ratadrabik.
  4. Put the original Ratadrabik into your graveyard due to the legend rule.
  5. Each other copy of Ratadrabik triggers, creating a nonlegendary token copy of Ratadrabik that is a 2/2 Zombie in addition to its other types.
  6. Repeat from step 2.[END OF COMBO STEPS]

Result:
  - Infinite creature tokens
  - Infinite death triggers
  - Infinite enters the battlefield
  - Infinite leaves the battlefield[END OF COMBO RESULT][END OF COMBO]

Other prerequisites:
  - All permanants must be on the battlefield
  - Ratadrabik in hand or in your graveyard.Liliana has at least three loyalty counters on it.
[END OF COMBO PREREQUISITES]
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