You control at least one creature with one or more +1/+1 counters on it.
You control at least one other creature.
Morselhoarder has exactly one or two -1/-1 counters on it.
Thornbite Staff attached to Xavier Sal.
Xavier Sal does not have summoning sickness.
Steps
Activate Xavier Sal's second ability by tapping it and sacrificing a creature.
When the creature dies, Xavier Sal triggers, untapping Xavier Sal.
Resolve the Xavier Sal ability from step 1, putting a +1/+1 counter on a creature you control and a -1/-1 counter on Morselhoarder.
Animation Module triggers, holding priority, activate Morselhoarder by removing a -1/-1 counter from it, adding ({1} magic symbol) .
Resolve the Animation Module trigger, causing you to pay ({1} magic symbol) to create a 1/1 Servo artifact creature token.
Repeat.
Once you have infinite +1/+1 counters among creatures you control, you may instead use Xavier Sal's first ability to get infinite copies of creature tokens you control.