The Crystal Slime

The crystal slime
While not as friendly as the average pink slime, these odd subspecies is still one of the more pleasent sights. They are commonly found in deep caves where almost no light enters. They thrive off of the glowing crystals that protrude out of the rocks, often taking the colour of the ones they digested, and starting to glow themselves. Despite possessing a wide array of colours, they can be recognised due to the occasional crystal shard floating within their gelatinous body, which tend to reflect light. They are known to be a miners best friend when it comes to monsters, as these slimes never bother others if they don’t bother them. The crystals aren’t even worth much, so the miners happily let them be. Not to mention, they are an excellent light source that is also free, which means a lot in the really deep caves.
Battle tactics:''
Now this is still not tested completely, but so far this specific subspecies has been shown to be weak against darker types of magic. As for all the other strenghts, it is capable of taking a considerable amount of punishment from all magical sources, especially fire.
For pet owners:''
These are a fairly normal choice amongst people, due to their beautiful looks and calm nature. It may not be suited for adventurers though, as their movements are lazy and slow. This is because despite having a digestive system strong enough to digest nearly anything, it is quite slow, and as a consequence the slimes themselves are lazy to do anything but munch on a crystal they wrapped themselves around. Sometimes, if not hungry, they’ll rather wrap around their owner in an attempt to show affection.