Jan Jansen, Chaos Crafter | Haunted One | Retribution of the Ancients

(and two other cards)

Artifact Creature that is a Gnome and/or Artificer

All permanents on the battlefield.
Jan Jansen and the additional Gnome or Artificer do not have a +1/+1 counter on them.
You control at least one additional artifact creature.

Activate
Jan Jansen's first ability by tapping it and sacrificing another artifact creature you control except the Gnome or Artificer.
Jan Jansen triggers, causing it and creatures you control that share a creature type with it to get +2/+0 and undying until end of turn.
Resolve the
Jan Jansen ability, creating two Treasure tokens.
Activate
Ashnod's Altar by sacrificing
Jan Jansen, adding ({C} magic symbol) ({C} magic symbol) .
When
Jan Jansen dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
Activate
Jan Jansen's first ability by tapping it and sacrificing the Gnome or Artificer.
When the Gnome or Artificer dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
Resolve the
Jan Jansen ability, creating two Treasure tokens.
Activate a Treasure by tapping and sacrificing it, adding ({B} magic symbol) .
Activate
Retribution of the Ancients by paying ({B} magic symbol) and removing the +1/+1 counter from
Jan Jansen and the other Gnome or Artificer, giving a creature -2/-2 until end of turn.
Repeat from step 4.