Is Ephemeral Shields legal in Standard, Modern, and Commander?

Ephemeral Shields is legal in: Modern, Pioneer, Legacy, Vintage, Commander, Pauper.

What type of card is Ephemeral Shields?

Ephemeral Shields is an Instant. Its oracle text reads: "Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.) Target creature gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)"