Is Netherborn Phalanx legal in Standard, Modern, and Commander?

Netherborn Phalanx is legal in: Modern, Legacy, Vintage, Commander.

What type of card is Netherborn Phalanx?

Netherborn Phalanx is a Creature — Horror. Its oracle text reads: "When this creature enters, each opponent loses 1 life for each creature they control. Transmute {1}{B}{B} ({1}{B}{B}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.) Power/Toughness: 2/4"

Netherborn Phalanx

Creature — Horror

When this creature enters, each opponent loses 1 life for each creature they control.

Transmute (, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)