Is Flitterstep Eidolon legal in Standard, Modern, and Commander?

Flitterstep Eidolon is legal in: Modern, Pioneer, Legacy, Vintage, Commander, Historic.

Flitterstep Eidolon

Q: What type of card is Flitterstep Eidolon?

Flitterstep Eidolon is an Enchantment Creature — Spirit. Its oracle text reads: "Bestow {5}{U} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)Flitterstep Eidolon can't be blocked.Enchanted creature gets +1/+1 and can't be blocked."

Enchantment Creature — Spirit

Bestow (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)<br>Flitterstep Eidolon can't be blocked.<br>Enchanted creature gets +1/+1 and can't be blocked.