Is Cryptic Serpent legal in Standard, Modern, and Commander?

Cryptic Serpent is legal in: Modern, Pioneer, Legacy, Vintage, Commander, Pauper, Historic.

Cryptic Serpent

Q: What type of card is Cryptic Serpent?

Cryptic Serpent is a Creature — Serpent. Its oracle text reads: "This spell costs {1} less to cast for each instant and sorcery card in your graveyard. *It slithers through the senses, constricting consciousness and poisoning perceptions.* Power/Toughness: 6/5"