How can you create a combo with Arena of the Ancients, Leyline of Singularity?
user
[START OF COMBO]This combo can be formed with Arena of the Ancients, Leyline of Singularity

Color identity: U
Mana cost: 
Steps:
  1. Leyline of Singularity causes all nonland permanents to be legendary.
  2. Arena of the Ancients prevents legendary creatures from untapping during their controller's untap steps.[END OF COMBO STEPS]

Result:
  - Creatures do not untap during their controller's untap step[END OF COMBO RESULT][END OF COMBO]

Other prerequisites:
  - All permanants must be on the battlefield
[END OF COMBO PREREQUISITES]
assistant