I know there isn't likely to be an official answer beyond "it makes for decent episodes" but I'd just like to hear some fan theories about how a TF continues to function in a decapitated state after the Headmaster pwns them. I mean, we've clearly seen that spark chambers are in the body somewhere and not in the head, yet Bulkhead and Sentinel Prime have continued to function with their heads lased off. Starscream doesn't count, he's an immortal freak. Waspinator is another freak, so it's also up in the air if he's representative of all Transformer, being a disgusting, AWFUL organic! I mean, how can he even live with hi-*ahem*, anyhoo... The head seems to be vitally important to function. Arcee's head is where her memory seems to have been stored, after all. So how does a TF continue to function and maintain their consciousness with their head off. Is the head just not a vital part? - Coeloptera
Given that in the cases of Bulkhead and Sentinel Prime they were able to "feel" what their bodies were doing/having done to them, I'd say there is some kind of remote connection that keeps all the parts of a Transformer "in contact" with the rest without the need for them to be physically touching. This would also go a long way in explaining the mechanics of Transformation itself (parts being able to rearrange themselves without having to keep some kind of central pathway/connection running through all of them, and/or needing tons of redundant systems to make sure that nothing disconnects completely from the central control/power source) as well as things like "mobile accessories" (trailers, Drones, parts that detach/reattach on their own, etc).
Megatron is unique, because he was quite dead as a head before being charged by the key in "Home is where the Spark is". Only after regaining his body did his spark return. Bulkhead was able to feel his body when not attached, and his spark was never extinguished, so it's safe to say those were key factors in his living after decvapitation. (same goes for Sentinel) Starscream IS dead. He has no spark, only the Allspark fragment in his head keeps him alive.
^ SO this. Megatron was dead and was revived as SPLIT LIP wrote. And Starscream is immortal till he has Allspark fragment in his head. Wondering if somehow you can remove this fragment and than he'd be dead?
It won't be for much longer if he keeps picking at it. Apparently he makes the clones by breaking off slivers. You'd think that if you had a tiny rock keeping you alive by being embedded in your body, you wouldn't break it up and remove it piece by piece...
I reckon it's simply a case of the spark still communicating with the head. The spark chamber probably has some technolgy that's linked to the head circuitry by some wireless means (mystical spark energy or some such intangible thing if you prefer an alternative to technology in this case). So, if you lop off a TF's head that head will continue to act alive as long as the spark is in the body and both sets of the technology providing the link are active. Take the spark from the chamber and I reckon the head would stop doing the things heads do. I think in Megatron's case his head was so badly damaged that the technology that provides the link to the spark in his body wasn't working, so when Sari's key affected his head it repaired that technology and the link was restored to the spark still in his body and the head came back to 'life' even though the spark in his chest had been alive all along. That said, I would've imagined Megatron would've been aware of the spark link thing and been more interested in finding his old body than making a new one. Unless he was planning to build his new body and then use it to find his spark and transfer it over. There's always a way around problems with these ideas.
The guy's a nutcase, what do you expect? Not a very severe case of insanity, but... No, he just tries to hard to be OMG OVERLOOOOORD!
