Is Themberchaud legal in Standard, Modern, and Commander?

Themberchaud is legal in: Legacy, Vintage, Commander.

Themberchaud

Q: What type of card is Themberchaud?

Themberchaud is a Legendary Creature — Dragon. Its oracle text reads: "Trample When Themberchaud enters, he deals X damage to each other creature without flying and each player, where X is the number of Mountains you control. You may exert Themberchaud as he attacks. When you do, he gains flying until end of turn. (An exerted creature won't untap during your next untap step.)"

Legendary Creature — Dragon

Trample

When Themberchaud enters, he deals X damage to each other creature without flying and each player, where X is the number of Mountains you control.

You may exert Themberchaud as he attacks. When you do, he gains flying until end of turn. (An exerted creature won't untap during your next untap step.)

Set Universes Within

Rarity Rare

Mana Value 7

Artist Edgar Sánchez Hidalgo

Collector # 28

Scryfall