When this Equipment enters, amass Goblins 1, then attach this Equipment to the amassed Army. (To amass Goblins 1, put a +1/+1 counter on an Army you control. It's also a Goblin. If you don't control an Army, create a 0/0 black Goblin Army creature token first.)
Equipped creature gets +1/+0 and has menace.
Equip {4}
