system
Given the following post, respond as if you're commenting on Reddit:
human
[King of the Hill] What the hell is shin jelly?

I work at a pharmacy and some 4 foot tall old guy waddled in and handed me a $20 bill poked onto a bayonet and asked for some shin jelly. (You ever see that show Squidbillies with that Dan Halen guy that has no knees? It was kind of like that) I've worked here for years and never heard of anything called shin jelly. He was going off about killing 50 men so I asked my boss  Apparently we even have different brands of it, like Sheldon's shin jelly. How commonly is it used that you'd have brand competition for shin jelly products and what exactly does shin jelly do?
gpt
It's a very niche product but a wonderful thing to have if you need it. You know shin splints? Shin jelly numbs that sharp pain and soothes it with an icy feeling. 

It doesn't work for cramps, or soreness, or tense muscles, or bone bruises. It's specifically for shin splints. That being said, it's not all that different than pain relief gel from a manufacturing standpoint so a lot of big brands make them.