When Wilhelt dies, Myrkul triggers, exiling Wilhelt from your graveyard and creating a token copy of Wilhelt that is an enchantment.
Cast Dress Down by paying ({1} magic symbol) ({U} magic symbol) .
When Dress Down enters the battlefield, it triggers, causing you to draw a card.
Activate Ashnod's Altar by sacrificing a Zombie, ({C} magic symbol) ({C} magic symbol) .
When the Zombie dies, the Wilhelt token triggers, creating a 2/2 Zombie creature token with decayed, which becomes a 1/1 Zombie without decayed due to Dress Down.