Is Overlord of the Floodpits legal in Standard, Modern, and Commander?

Overlord of the Floodpits is legal in: Standard, Modern, Pioneer, Legacy, Vintage, Commander, Historic.

Overlord of the Floodpits

Q: What type of card is Overlord of the Floodpits?

Overlord of the Floodpits is an Enchantment Creature — Avatar Horror. Its oracle text reads: "Impending 4—{1}{U}{U} (If you cast this spell for its impending cost, it enters with four time counters and isn't a creature until the last is removed. At the beginning of your end step, remove a time counter from it.) Flying Whenever this permanent enters or attacks, draw two cards, then discard a card. Power/Toughness: 5/3"

Enchantment Creature — Avatar Horror

Impending 4— (If you cast this spell for its impending cost, it enters with four time counters and isn't a creature until the last is removed. At the beginning of your end step, remove a time counter from it.)