On the cusp of change

I think I might be nearing a crossroads with my parenting (skills?). The boy is 5 soon and I think my drop down to your level and have some fun approach isn’t really suitable for full time deployment any more. The boy doesn’t seen to think there is a source of natural authority in the house, so we have to keep on pretending to grass him up to his school’s headmistress when he’s an annoying little sod. 
Equally asking him to do something usually entails a full and frank discussion that starts with “Well…” or the infamous “But…”. And then descends into threats of decapitation (on his part I hasten to add) or throwing all our stuff in the rubbish bin. I think my behaviour is probably a subconscious (except now I’m thinking about it, it must be conscious) attempt to do things differently from my Dad but whereas I turned into the worlds shyest boy, our boy is in danger of getting a bit out of hand. 
Overall though I’m not worried. Some of the little boys at his school are almost feral- running about spitting, punching, pinching, shoving people over, and making very odd hissing noises. There are one or two that actually are unmanageable so their mums seem to have given up and just offer a weak, “[insert boys name] please don’t do that, there’s a good boy. Oh.” whenever their child seems hell bent on updating Lord of the Flies into a 21st century setting. What does worry me is the boys potential to head down that road. 
Perhaps I need to switch my Clone Trooper mask (the goodies) for a Storm Trooper one (the baddies) and move him temporarily to the holding cells. I hear there’s a free cell in Block one-one-three-eight…