Cacophony Unleashed

When Cacophony Unleashed enters the battlefield, if you cast it, destroy all nonenchantment creatures.
Whenever Cacophony Unleashed or another enchantment enters the battlefield under your control, until end of turn, Cacophony Unleashed becomes a legendary 6/6 Nightmare God creature with menace and deathtouch. It's still an enchantment.

When this enchantment enters, if you cast it, destroy all nonenchantment creatures.
Whenever this enchantment or another enchantment you control enters, until end of turn, this enchantment becomes a legendary 6/6 Nightmare God creature with menace and deathtouch. It's still an enchantment.