Etali, Sleeping Chaos

Partner with Nikias, Tamer of Etali (When this creature enters, target player may put Nikias into their hand from their library, then shuffle.)

Whenver Etali attacks, roll a d 20. Activate only if you control a Human
1-9 Etali gains first strike until end of turn.
10-19 Etali gains first strike and +3/+3 until end of turn.
20 Etali gains first strike and +3/+3 until end of turn. Then exile the top three cards of defending player's library. You may play one of them without paying the mana cost