Threefold Thunderhulk (The Lost Caverns of Ixalan)

Artifact Creature Ñ Gnome - This creature enters with three +1/+1 counters on it.
Whenever this creature enters or attacks, create a number of 1/1 colorless Gnome artifact creature tokens equal to its power.
{2}, Sacrifice another artifact: Put a +1/+1 counter on this creature.