Is Sinuous Striker legal in Standard, Modern, and Commander?

Sinuous Striker is legal in: Modern, Pioneer, Legacy, Vintage, Commander.

What type of card is Sinuous Striker?

Sinuous Striker is a Creature — Snake Warrior. Its oracle text reads: "{U}: This creature gets +1/-1 until end of turn. Eternalize—{3}{U}{U}, Discard a card. ({3}{U}{U}, Discard a card, Exile this card from your graveyard: Create a token that's a copy of it, except it's a 4/4 black Zombie Snake Warrior with no mana cost. Eternalize only as a sorcery.)"

Sinuous Striker

Creature — Snake Warrior

: This creature gets +1/-1 until end of turn.

Eternalize—, Discard a card. (, Discard a card, Exile this card from your graveyard: Create a token that's a copy of it, except it's a 4/4 black Zombie Snake Warrior with no mana cost. Eternalize only as a sorcery.)