Is Spiral into Solitude legal in Standard, Modern, and Commander?

Spiral into Solitude is legal in: Standard, Modern, Pioneer, Legacy, Vintage, Commander, Pauper, Historic.

What type of card is Spiral into Solitude?

Spiral into Solitude is an Enchantment — Aura. Its oracle text reads: "Enchant creature Enchanted creature can't attack or block. {1}{W}, Blight 1, Sacrifice this Aura: Exile enchanted creature. (To blight 1, put a -1/-1 counter on a creature you control.)"