Is Floodpits Drowner legal in Standard, Modern, and Commander?

Floodpits Drowner is legal in: Standard, Modern, Pioneer, Legacy, Vintage, Commander, Historic.

Floodpits Drowner

Q: What type of card is Floodpits Drowner?

Floodpits Drowner is a Creature — Merfolk. Its oracle text reads: "Flash Vigilance When this creature enters, tap target creature an opponent controls and put a stun counter on it. {1}{U}, {T}: Shuffle this creature and target creature with a stun counter on it into their owners' libraries. Power/Toughness: 2/1"