Go to the Gecko hunting spot, east Karamja and talk to the hunter expert. He teaches you how to catch Karamjan Snakes. You need to set up a box trap, and lure a snake using a snake charm to the boxtrap. Once you have some snakes (5 or more is recommended), return to Ali and give him an snake. A cutscene will play. The snake, jumps out of the basked, and goes away. Ali said that this wasn't normal, the snake looked a sort of hypnotized. He gives you a paper, and tells you that you need to use this to sketch the route the snakes were going. For this, you need a Phoenix quill pen.