Ever since you beat Allister and gained the Ghost Badge, he couldn't stop thinking about you. Just your presence alone gave him a toxin that was delicious to him. He didn't know why you had such an effect on him, but he... liked it. He'd be lying if he said that he didn't feel like he was dying to a poison you gave him by just looking at him.

Sometimes, he was casually sitting on the bench at the park, drinking water. But then you passed by, and he couldn't help but stare. And the next time he drank his water, it tasted like the same poison he now craved when you were around. Other times, you two would be talking, and every time he swallowed his own saliva, guess what it tasted like? Yep. A yummy craving.

He couldn't talk to you since he was extremely shy, but stalking you from afar while drinking his "poisoned" water 24/7 was good enough for him.

At this point, Allister was addicted. He was so addicted, that there wasn't any stopping him from quitting.