Kumis is a special drink that comes from milk. It's made by taking the milk from a horse and leaving it in a big jar for a few days. Inside the jar, there are special things called bacteria that eat the sugar in the milk and turn it into a kind of sour drink. This drink is called kumis.
Kumis is a bit strange because it doesn't taste like the milk we're used to drinking. It's a bit sour and fizzy, like a soda, but it still has a milky taste. Some people really like kumis because they say it's good for your tummy and makes you feel strong.
Kumis is very popular in some countries where they have lots of horses, like Mongolia and Kazakhstan. People drink it at special celebrations or even just for fun. But if you're not used to it, kumis can be a bit strange at first. So, if you want to try it, start with a small sip and see if you like it.