Is Shrewd Hatchling legal in Standard, Modern, and Commander?

Shrewd Hatchling is legal in: Modern, Legacy, Vintage, Commander.

Shrewd Hatchling

Q: What type of card is Shrewd Hatchling?

Shrewd Hatchling is a Creature — Elemental. Its oracle text reads: "This creature enters with four -1/-1 counters on it. {U/R}: Target creature can't block this creature this turn. Whenever you cast a blue spell, remove a -1/-1 counter from this creature. Whenever you cast a red spell, remove a -1/-1 counter from this creature. Power/Toughness: 6/6"