Avdehx, the Cloud Timer

Flying
At the beginning of your upkeep, you may pay {1}{w}{u} any number of times. If you do, put a cloud counter on Avdehx, the Cloud Timer for each time this was paid. Then if there are 12 or more cloud counters on Avdehx, the Cloud Timer, return all creatures opponents control to their owners' hands and remove all cloud counters.