Weapon Rack
Artifact
This artifact enters with three +1/+1 counters on it.
: Move a +1/+1 counter from this artifact onto target creature. Activate only as a sorcery.
No weapon stays on the rack for long in the Burning Yard.
Illustrated by
Throne of Eldraine#236CommonEnglishLegality
Rulings
Once Weapon Rack runs out of +1/+1 counters, it remains on the battlefield. You can activate its last ability, but it won't do anything.
If Weapon Rack has left the battlefield or has no +1/+1 counters on it by the time its activated ability resolves, you won't put a +1/+1 counter on the target creature. If the creature becomes an illegal target or can't have a +1/+1 counter put onto it for some other reason, you won't remove a +1/+1 counter from Weapon Rack.
The +1/+1 counters on Weapon Rack won't affect it unless it somehow becomes a creature.