How do i create a demon who does nothing but run in place constantly?

[PeceMan]

For decoration purposes, i want him to be like on a treadmill, so he can't notice the player

 

 

I was thinking giving him speed 0 and the having him agro some invisible monster, but i dont have much place, so won't he eventually kill him, if i dont manage to place both far enough apart? And won't he eventually get bored of the invisible monster? I was thinking making him friendly, but I'd like the player to be able to kill him

 

Does anyone have a better idea?

[Rainne]

If the only things it'll do are run in place and die, perhaps whip up a new actor from scratch that uses the demon's sprites and is killable. If you want it to be fully functional if attacked, perhaps derive from the original demon actor and replace its idle state with an appropriate animation and which doesn't call A_Look; then I think it would only respond to actually being attacked.