Requires

Blood Funnel must be on the battlefield. Corpse Dance must be in hand. Witch Engine must be on the battlefield. Witch Engine does not have summoning sickness. Mana needed:

Steps

1. Activate Witch Engine by tapping it.
2. Holding priority, cast Corpse Dance with buyback by paying due to Blood Funnel.
3. Blood Funnel triggers, causing you to sacrifice Witch Engine.
4. Resolve Corpse Dance, returning Witch Engine from your graveyard to the battlefield, giving it haste, and returning Corpse Dance to your hand.
5. Resolve the Witch Engine ability from step 1, adding and failing to give an opponent control of Witch Engine as it is a new object.
6. Repeat.

Results