Activate Ashling three times by paying ({3} magic symbol) ({R} magic symbol) ({R} magic symbol) ({R} magic symbol) , putting three +1/+1 counters on it, then removing all +1/+1 counters from it and dealing that much damage to each creature.
Each creature dealt damage by Ashling dies due to Ashling's deathtouch.
Scythe of the Wretched triggers for each creature that dies this way, returning them to the battlefield under your control, ensuring that Ashling is returned last so that Scythe of the Wretched will be attached to it.
You may repeat this combo as desired.
Results
Gain control of all creatures without indestructible during each of your turns.