Is Skeletonize legal in Standard, Modern, and Commander?

Skeletonize is legal in: Modern, Legacy, Vintage, Commander, Pauper.

Skeletonize

Q: What type of card is Skeletonize?

Skeletonize is an Instant. Its oracle text reads: "Skeletonize deals 3 damage to target creature. When a creature dealt damage this way dies this turn, create a 1/1 black Skeleton creature token with "{B}: Regenerate this token." *Fire burns away both flesh and freedom.*"

Instant

Skeletonize deals 3 damage to target creature. When a creature dealt damage this way dies this turn, create a 1/1 black Skeleton creature token with ": Regenerate this token."