Actually you can't. But you can try chasing him: You get the toy bird in the toy store, because the Pet Shope owner said that to find Eddie's (the snake) favorite snack. Well, apparently, snakes eat birds. So, after getting the bird, you go the the MacGuffin's (Mall right, 3rd floor) store and click the shaking Port-a-potty, indicating that Eddie is in there. Then go the the Sizzle Tanning (Mall right, 1st floor) shop and click on the shaking tanning bed. Eddie will hop out and slither away again. That darn snake! Finally, he is in the Chinese food stand at the Mall Atrium. As you can see, Eddie is behind the counter, but he's too fast for you to catch. What you need to do now is get the toy bird and lure Eddie out. He will eat it, then slither away. That's it. The Pet Shop Owner said that you shouldn't bother catching him, he'll catch him in the morning. So basically, you can't catch him, the owner will.