Is Tolarian Terror legal in Standard, Modern, and Commander?

Tolarian Terror is legal in: Standard, Modern, Pioneer, Legacy, Vintage, Commander, Pauper, Historic.

What type of card is Tolarian Terror?

Tolarian Terror is a Creature — Serpent. Its oracle text reads: "This spell costs {1} less to cast for each instant and sorcery card in your graveyard. Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)"