In Real Life, there are generally two classes of spice substances that can be considered in the realm of Blazing Inferno (each link to The Other Wiki):
- Capsaicin, found in chili peppers and anything based on them.
- Allyl isothiocyanate, found in mustard, horseradish, wasabi, and related plants (within the cabbage family Brassicaceae).
Outside of those two, there's another group that is considered to be in Blazing Inferno territory:
- hydroxy-alpha sanshool, found in Sichuan peppercorns.
- Resiniferatoxin and Tinyatoxin, which are hundreds of times more potent than capsaicin. The latter is even categorized as a neurotoxin. Don't worry though, by the time you ingest enough to poison you, death will probably be the last thing you fear.
Capsaicin is virtually insoluble in water, so washing your mouth with water, soda, or tea after you bite more than you can chew is rather ineffective. It is, however, readily dissolved in fats or ethanol, so a glass of non-skim milk or a shot of liquor would make you feel better almost instantly. This is why creamy sauces (like ranch dressing) go well with spicy foods like hot wings (creamy sauces are typically fatty so help control the spicy sensation) and why poppers (gutted jalapenos filled with cheese sauce) aren't as spicy as they look (most of the spice has been removed; what's left is tempered by the fatty cheese). It's also possible to use a common alcohol-based mouthwash to wash it out. Contrary to popular belief, capsaicin (and sauces made from it), aren't actually hot (temperature-wise), or corrosive at all. It behaves the way it does because it mimics a neurotransmitter in mammals,note interacting with the nerve channel that is only supposed to open when you are being burned, at 70F. Since body temperature is definitely above this, it effectively makes your brain think you're being burned when you actually aren't.note In extreme concentrations, it can cause temporary injury, but that's only because the body responds to it as it would an actual burn - the resulting inflammation injury is similar to frostbite. It should be noted that no chili peppers, even the infamous Carolina Reaper, are nearly enough to cause this, it takes nearly pure capsaicin to cause it.
It's also worth noting that Capsaicin and Allyl isothiocyanate have very different chemical mechanisms and very different results when consumed. Capsaicin produces a burning sensation on the surfaces it touches (lips, tongue, skin) by activating the heat/pain receptors in the relevant tissues,note while Allyl isothiocyanate instead produces a vapor that attacks the nasal passages and sinuses (it does partially activate some of the same pain receptors as capsaicin, hence the widely-recognized similarity) and is a lachrymator;note it's largely for this reason that while capsaicin has a wide array of foods it can be "safely" applied to, allyl isothiocyanate is primarily (although not solely) good at enhancing meaty flavors (as the way it causes "heat" interacts with meaty flavor somehow)—hence the association of horseradish with roast beef, mustard with sausages and other cured meats (e.g. pastrami), and wasabi with fish (particularly meatier fishes like tuna). This difference in chemical mechanisms also means that a person who is adapted to capsaicin may find themselves overwhelmed by a relatively mild dose of Allyl isothiocyanate, and vice versa.
The hydroxy-alpha sanshool has a unique "numbing-spicy" characteristic that makes it quite good (and prized in Sichuan cuisine) for complementing one of the others, and particularly capsaicin, in a sauce or other preparation, but mostly useless for making a blazing-hot sauce on its own. Oh, and there's Piperine, found in black pepper and other peppercorns. Piperine adds a bite and a kick, but because piperine's mechanism of action is largely the same as capsaicin, but orders of magnitude less intense—pure piperine is "only" about as spicy as a "mild" habanero—it is very difficult to make a really fiery sauce with. However, like sanshool, it's an excellent accompaniment to the others, although combinations with piperine and allyl isothiocyanate lead to more interesting flavors than ones with piperine and capsaicin (since, again, piperine's heat is almost the same kind as capsaicin's, just weaker).
There are several real-life "hot sauces" that aren't actually sauces at all. They're either novelty bottles of pure capsaicin in a vegetable oil carrier, or they're "Food-Service Grade capsaicin", intended for use only as an ingredient, not a condiment. Such "sauces" can be lethally toxic when consumed at condiment levels. Not to mention capsaicin itself isn't just for condiment or ingredient uses—it's also one of the main compounds found in many self-defense sprays, and it is not something you would want to play around with in any form, given that just a few drops of the pure stuff becoming aerosolized can clear out entire rooms and leave the former occupants in agonizing, burning pain for extended periods.
It bears noting that while there are innumerable brands of hot sauce out there with names like Torch, Hell's Breath, and the like, many are actually the same sauce - as in "made at the same time, using the same recipe, by the same manufacturer, just put into bottles with different labels". This naturally hasn't stopped hot sauce aficionados from getting into huge fights over which is the best.