dam them troublesome alians, eh? ;) What your doing is a for each loop: for i in alians. Basically it's going to go through the list of alians, and i gets assigned to the new alian, so you would use something like: i.move() rather than alians[i].move etc HTH, Thanks, Tyler Littlefield Web: tysdomain.com email: tyler@xxxxxxxxxxxxx My programs don't have bugs, they're called randomly added features. ----- Original Message ----- From: BlueScale To: programmingblind@xxxxxxxxxxxxx Sent: Friday, April 17, 2009 5:17 AM Subject: Python (Trouble with Aliens!) Hi, I am having some trouble with my aliens. Here's the code: for i in aliens: aliens[i].move() if aliens[i].getxpos() == x: lockOn.play() The error I am getting is: TypeError: object cannot be interpreted as an index Can someone please help me make my aliens behave better? Thanks