Is The Master, Mesmerist legal in Standard, Modern, and Commander?

The Master, Mesmerist is legal in: Legacy, Vintage, Commander.

The Master, Mesmerist

Q: What type of card is The Master, Mesmerist?

The Master, Mesmerist is a Legendary Creature — Time Lord Rogue. Its oracle text reads: "{T}: Target creature an opponent controls with power less than or equal to The Master's power gains skulk until end of turn. Goad it. (A creature with skulk can't be blocked by creatures with greater power.) Whenever a creature with skulk deals combat damage to one of your opponents, put a +1/+1 counter on The Master and draw a card. Power/Toughness: 3/3"

Legendary Creature — Time Lord Rogue

: Target creature an opponent controls with power less than or equal to The Master's power gains skulk until end of turn. Goad it. (A creature with skulk can't be blocked by creatures with greater power.)