Is Sproutback Trudge legal in Standard, Modern, and Commander?

Sproutback Trudge is legal in: Legacy, Vintage, Commander.

Sproutback Trudge

Q: What type of card is Sproutback Trudge?

Sproutback Trudge is a Creature — Fungus Beast. Its oracle text reads: "This spell costs {X} less to cast, where X is the amount of life you gained this turn. Trample At the beginning of your end step, if you gained life this turn, you may cast this creature from your graveyard."