The Disciple of Nissa is a rare Legendary Creature — Elf Wizard card from Unknown Event (UNK), collector number RG01b. Current market price: $41.04, TCGplayer market prices via Scryfall.
Whenever the Disciple of Nissa attacks, you may pay {X}{X}{X}{G}{G}. When you do, create X tokens that are copies of different Nissa planeswalkers chosen at random. They each enter with an additional loyalty counter. (There are currently eleven. Yes, Nissa, Sage Animist counts. Perhaps look up the list and roll a D20?)