Boomerang Oct 5, 2010 The Smurfs S1 Ep 24 The Purple Smurfs & Ep 23 Haunted Smurfs

Season 1 Episode 24 The Purple Smurfs
A purple fly bites Lazy and he turns purple, causing him to say "GNAP GNAP!" and bite the other Smurfs, turning them into nasty, evil, angry purple smurfs as well.

Season 1 Episode 23 Haunted Smurfs
The Smurfs leave to look for food and enter a castle that they think is haunted.