Saya, Emrakul's Envy

When Saya, Emrakul's Envy enters, if you didn't cast it from your hand, create two green 1/1 elf creature tokens.
{c}{ut}: Sacrifice ten elf tokens, create a 10/10 colorless eldrazi creature token.
Whenever one or more eldrazis youc control leave the battlefield, create a green 1/1 elf creature token.