What codes can I write to make a CO do stuff?

So, I can make a simple CO that does an animation, but I was wondering if there was something I could write to make them do other stuff like moving and killing Juni if she touches it.
I've searched on google but I couldn't find a tutorial on it besides the animation one, but I've seen COs that walk around, so it must be possible.

custom objects walking around are just bigger files that have a lot of frames that stretch over the whole area which is walked. there should be another somewhwat recent thread findable with [search] on that topic. also, SiamJai made a post a bit ago about a nightsky car CO animation, there you'll see the concept.
custom objects are also completely inactive, that means they are nonsolid and cannot (directly) have any effect on the player. you could try putting a kill tile, but that's stationary etc, so probably not really what you want.