Is Chartooth Cougar legal in Standard, Modern, and Commander?

Chartooth Cougar is legal in: Legacy, Vintage, Commander, Pauper.

What type of card is Chartooth Cougar?

Chartooth Cougar is a Creature — Cat Beast. Its oracle text reads: "{R}: This creature gets +1/+0 until end of turn. Mountaincycling {2} ({2}, Discard this card: Search your library for a Mountain card, reveal it, put it into your hand, then shuffle.)"