Is Mystic Decree legal in Standard, Modern, and Commander?

Mystic Decree is legal in: Legacy, Vintage, Commander.

What type of card is Mystic Decree?

Mystic Decree is a World Enchantment. Its oracle text reads: "All creatures lose flying and islandwalk."

World Enchantment

All creatures lose flying and islandwalk.

Set Homelands

Rarity Rare

Artist Liz Danforth

Enchantment Flying Commander Legacy Vintage