Is Sphinx of Lost Truths legal in Standard, Modern, and Commander?

Sphinx of Lost Truths is legal in: Modern, Legacy, Vintage, Commander.

What type of card is Sphinx of Lost Truths?

Sphinx of Lost Truths is a Creature — Sphinx. Its oracle text reads: "Kicker {1}{U} (You may pay an additional {1}{U} as you cast this spell.) Flying When this creature enters, draw three cards. Then if it wasn't kicked, discard three cards. Power/Toughness: 3/5"