Teal Slime

Now coming in many varieties such as fire, ice, poison, etc. They were the easiest for wizards to tamper with, being the simplest beings, and have become far more populous than in previous times, definitely migrating from living only deep underground in the darkness. More appear when you kill them, so watch out.

Teal Elemental Slimes are like normal Slimes, except they've been magically imbued with ice elemental properties.
Icedick slime

A Rare Spawn Teal Slime which has spawned with a unique name, along with a very slight darkened colouration.Titled Icedick. o;

It is not known how they are able to be ice elemental slimes without freezing, but then again, it is not known how wizards have done ANY of the things they've done either. It's easy just handwaved with "dark sinister magical experiments" and it's best not to hurt your head over thinking about it.