Predator on Annie makes you an incredibly scary engage tool for your team with the ability to roam to side lanes and snowball the game.
Annie can reliably proc Cheap Shot thanks to her stun. Once you get *Rylai's you can continuously proc the true damage with Tibber's Aura**.
Eyeball Collection is fantastic for capitalizing on successful Predator roams but snowballing your kills/assist into more AP.
Ingenious Hunt's bonus item CDR keeps your Predator boots on a short cooldown allowing you to futher snowball the game with more roams and teamfight engages.
Celerity synergizes well with Predator granting you a bit of extra AP while sprinting at the enemy team and looking to engage. The extra MoveMent Speed is also great for staying in range for harass during the laning phase.
Scorch's extra bit of chip damage is pivotal in whittling away the enemy to keep them in kill threat and all-ins.