Is Mourning Thrull legal in Standard, Modern, and Commander?

Mourning Thrull is legal in: Modern, Legacy, Vintage, Commander, Pauper.

Mourning Thrull

Q: What type of card is Mourning Thrull?

Mourning Thrull is a Creature — Thrull. Its oracle text reads: "({W/B} can be paid with either {W} or {B}.) Flying Whenever this creature deals damage, you gain that much life. *During their ascent to spirithood, patriarchs of Orzhova shed both flesh and emotion. This earthly slag is collected and formed into thrulls.* Power/Toughness: 1/1"