Jaylah, Zulian Bountyhunter

Whenever another Elf enters the battlefield
under your control, put a +1/+1 counter on target Elf.
{g}, {t}: Create X 1/1 green Elf creature tokens, where X is the number of Elves that entered the battlefield this turn. Exile Jaylah, Zulian Bountyhunter at the beginning of the next
end step.