For really super-super-hot use fresh habanero/'scotch bonnet' peppers, the light green ones (not red). Chop up really fine including seeds and add a pinch at a time (no point in chopping up much more than a half-teaspoon at one go). Wash your hands with soap and water after chopping them (peppers and/or hands). Most so-called hot peppers aren't really that hot. These ones really are.

Still only about half as hot as a Naga Bhut Jolokia.

(Though I have to say, eating shit just because it's ridiculously hot is dumb. Eat things that taste nice (pleasant chilli heat being a part of that))

Habanero != Scotch Bonnet

My brother used to make his own curry from base ingredients. You end up with stupid amounts of different spices and using teeny tiny amounts of each.

I know there's hotter, these you can generally find at your local supermarket [YMMV], and measure without a microgram scale.

Close enough in size, appearance and effectiveness.

So, by "habanero/'scotch bonnet'" you meant that they're equivalent not synonymous? 'Cos that's not how I read it, and I suspect the same for Kos.

They're cousins!