Bela, One with the Swarm

Vigilance
At the beginning of your upkeep, if a
creature entered the battlefield last turn,
create 2 1/1 green and white butterfly
creature tokens with flying.
Sacrifice 7 butterflies, create a legendary
artifact token with " At the beginning of your
upkeep, create 3 5/5 Swarm creature tokens
with flying and vigilance."