Since rengar feels weaker because of the counter play added why not add counter-counter play ? >:D

Ok this is a rework idea for bonetooth necklace that i thought pretty interesting.

-whenever rengar kill an ennemy champion or gain a takedown within 1.5secs of damaging them, rengar obtain a bonetooth necklace stack. He can only gain 1stack by ennemy champion.

-rengar can change a bonetooth stack by one of the following bonus:

   •rengar 1st aa agaisnt an ennemy champion remove               
    10 armor and apply a mark, the mark reduce shield 
    and incoming shields by 50% for 1.5secs
    (Cd : 10seconds)

   •at the activation of battle roar, gain cc imun for
    1secs  and damages imun for 0.4secs ( ap rengar
     Go brrr)

   •consuming 4fero stacks grants you invisibility for 
    1 secondes
 
    •bola strike crosses unites and the 1st ennemy hit      
     Lose 60% of his bonus armor. (Last for 3 secs)
  
    •activate thrill of the hunt now  grant 2secs of invis
     after 1. The mark only appear when the invis 
     Become a stealth ( 3seconds after thrill of the hunt
     Has been casted)

     •gain 10% ad

If rengar gain a bonetooth necklace stack but already have 4 bonus, automatically, one of his item that has no active gain the tiamat active ( 110% total ad ).