Is Komainu Battle Armor legal in Standard, Modern, and Commander?

Komainu Battle Armor is legal in: Legacy, Vintage, Commander.

Komainu Battle Armor

Q: What type of card is Komainu Battle Armor?

Komainu Battle Armor is an Artifact Creature — Equipment Dog. Its oracle text reads: "Menace Equipped creature gets +2/+2 and has menace. Whenever this creature or equipped creature deals combat damage to a player, goad each creature that player controls. Reconfigure {4} ({4}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)"

Artifact Creature — Equipment Dog

Menace

Equipped creature gets +2/+2 and has menace.

Whenever this creature or equipped creature deals combat damage to a player, goad each creature that player controls.

Reconfigure (: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)