Is Thijarian Witness legal in Standard, Modern, and Commander?

Thijarian Witness is legal in: Legacy, Vintage, Commander.

Thijarian Witness

Q: What type of card is Thijarian Witness?

Thijarian Witness is a Creature — Alien Cleric. Its oracle text reads: "Flash Bear Witness — Whenever another creature dies, if it was attacking or blocking alone, exile it and investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")"

Creature — Alien Cleric

Flash

Bear Witness — Whenever another creature dies, if it was attacking or blocking alone, exile it and investigate. (Create a Clue token. It's an artifact with ", Sacrifice this token: Draw a card.")