Is Ascending Aven legal in Standard, Modern, and Commander?

Ascending Aven is legal in: Legacy, Vintage, Commander, Pauper.

What type of card is Ascending Aven?

Ascending Aven is a Creature — Bird Soldier. Its oracle text reads: "Flying This creature can block only creatures with flying. Morph {2}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)"