Crystalline Crawler + Fain, the Broker + Reassembling Skeleton + Thornbite Staff

B identity

Commander legal

The 4 combo pieces

What must be in place

Thornbite Staff attached to Fain.
Fain does not have summoning sickness.

How to execute it

  1. Activate Fain's first ability by tapping it and sacrificing Reassembling Skeleton.
  2. Reassembling Skeleton dies, triggering Fain, untapping Fain.
  3. Resolve the Fain ability from step 1, putting two +1/+1 counters on Crystalline Crawler.
  4. Activate Crystalline Crawler's first ability twice by removing two counters from it, adding {B}{B}.
  5. Activate Reassembling Skeleton by paying {1}{B}, returning it from your graveyard to the battlefield tapped.
  6. Repeat.

What the combo produces