Is Harrowing Swarm legal in Standard, Modern, and Commander?

Harrowing Swarm is legal in: Historic.

What type of card is Harrowing Swarm?

Harrowing Swarm is a Sorcery. Its oracle text reads: "Manifest dread. Then each face-down creature you control gains "This permanent costs {2} less to turn face up" and "When this permanent is turned face up, if it's a creature, put a +1/+1 counter on it.""

Harrowing Swarm

Sorcery

Manifest dread. Then each face-down creature you control gains "This permanent costs less to turn face up" and "When this permanent is turned face up, if it's a creature, put a +1/+1 counter on it."