Helix of Fervor

Helix of Fervor enters the battlefield tapped.
Whenever a player casts a spell, put a charge counter on Helix of Fervor.
{3}: Helix of Fervor becomes an artifact creature with haste and "this creature's base power and toughness are each equal to the number of charge counters on this permanent". Sacrifice it at end of turn.
Only one helix can cause so much destruction.