Threefold Thunderhulk

Threefold Thunderhulk enters with three +1/+1 counters on it.
Whenever Threefold Thunderhulk 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 Threefold Thunderhulk.

The Lost Caverns of Ixalan

Threefold Thunderhulk enters the battlefield with three +1/+1 counters on it.
Whenever Threefold Thunderhulk enters the battlefield 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 Threefold Thunderhulk.

The Lost Caverns of Ixalan Promos

If Threefold Thunderhulk leaves the battlefield while its triggered ability is on the stack, use its power as it last existed on the battlefield to determine how many Gnomes to create.