Is Carnifex Demon legal in Standard, Modern, and Commander?

Carnifex Demon is legal in: Modern, Legacy, Vintage, Commander, Historic.

What type of card is Carnifex Demon?

Carnifex Demon is a Creature — Phyrexian Demon. Its oracle text reads: "Flying This creature enters with two -1/-1 counters on it. {B}, Remove a -1/-1 counter from this creature: Put a -1/-1 counter on each other creature. *Every contagion has a host.* Power/Toughness: 6/6"