Is Muddle the Mixture legal in Standard, Modern, and Commander?

Muddle the Mixture is legal in: Modern, Legacy, Vintage, Commander, Pauper.

What type of card is Muddle the Mixture?

Muddle the Mixture is an Instant. Its oracle text reads: "Counter target instant or sorcery spell. Transmute {1}{U}{U} ({1}{U}{U}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)"

Muddle the Mixture

Instant

Counter target instant or sorcery spell.

Transmute (, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)