THC infused foods are actually quite simple to make, and no spraying is needed.

THC is fat soluble so at the most basic level, infusing butter with cannabis flower will yield cannabutter which can then be used as a substitute for butter in just about any dish eg. The classic pot brownies you hear of.

The only complexity is dosing, which can be somewhat estimated if you can guess the potency of the flower. It's all a bit back of the napkin math, but you can get a decent estimate. One of my side projects (learning Vue.js) was a edible calculator for doing just this: http://www.scientificedibles.com

I actually know the CEO of a startup (called tCheck) that's selling pocket spectrometers for measuring butter (and other cannabis infused ingredients) potency quickly and accurately -- I got to tour their lab once, it's some pretty cool tech!

THC is also alcohol soluble, forming the basis of most tinctures and mouth sprays. Also scary names like “green dragon”, which are just higher volume alcohol based solutions that should probably not be consumed by anyone who doesn’t plan to get extraordinarily fucked up.

Slight bit of complexity there, THC-A usually needs to be decarboxylated into THC via heating to a certain temperature before infusion or the resulting butter is pretty mild.

Yeah I didn't mention that in the interest of brevity. Decarb is definitely necessary.

It seems like spraying some Skittles would be easier than spending time baking brownies, but I have no experience in this area.

Spraying is easy Yes, but getting the distillate to do it with is more complicated. You need to basically do the same process by either emulating it by infusing alcohol, or buy distillate outright which is much harder to find. My guess is a lot of these fake eibles actually exist in legal states, where distillate can be found easily. These fake products rely on the consumer being unaware of the fakeness, overstating the dosage (300mg) and under dosing the actual edibles by diluting the distillate spray to reduce costs.

That calculator is very nice!