Is Grim Giganotosaurus legal in Standard, Modern, and Commander?

Grim Giganotosaurus is legal in: Legacy, Vintage, Commander.

Grim Giganotosaurus

Q: What type of card is Grim Giganotosaurus?

Grim Giganotosaurus is a Creature — Dinosaur. Its oracle text reads: "{10}{B}{G}: Monstrosity 10. This ability costs {1} less to activate for each creature with power 4 or greater your opponents control. (If this creature isn't monstrous, put ten +1/+1 counters on it and it becomes monstrous.) When this creature becomes monstrous, destroy all artifacts and creatures other than this creature. Power/Toughness: 10/10"

Creature — Dinosaur

: Monstrosity 10. This ability costs less to activate for each creature with power 4 or greater your opponents control. (If this creature isn't monstrous, put ten +1/+1 counters on it and it becomes monstrous.)