In many jurisdictions, the **self-defense** defense for homicide rests on the state of the mind of the suspect, insofar as it can be determined, and failing that on a "reasonable man" standard.

- Presumably **Bob** genuinely felt threatened by **Charlie** and says so afterwards. "I thought he/it/whatever was trying to harm me. I didn't know it was a harmless actor." If he ever says "I knew it was an actor" Bob's defense is sunk.
- The well-documented and extensive efforts by Alice and Darren to fool **Bob** should support Bob's statement. Say the court/jury believes that it was reasonable (or at least "not entirely unreasonable") for Bob to be afraid.
- Since the perceived self-defense would apply *even if* Bob thought the attacker was human, thinking that it was non-human should make little difference. Except that it would further showcase the degree to which Bob was fooled to see a threat. 
- If the whole endeavor by **Alice** and **Darren** broke laws, the death *might* fall into felony homicide in some jurisdictions. This one could come to technicalities because Bob wasn't their accomplice. Otherwise, Darren's track record might prevent the two from being charged for negligent homicide.