From TMW: rEvolt
May mutate 1 attribute up to 10%.
Santa Slimes cruise around the snowy landscape of Nivalis in the snow field, just south of the town. They are a happy monster generally speaking, and are able to emote, letting you know their general feelings.
The Santa Slimes are bosses of the Rudolph Slimes, and will continually spawn new slimes to replace their destroyed groups. If you attack the Santa Slime, you will have all of his "mob" attack you instantly, and on the reverse side, if you kill the Santa Slime, you kill the whole mob in an instant.
Keep in mind, if you kill the Santa Slime, the Rudolph Slimes will not drop anything, but will lose whatever it is that they are holding. This is important if you think one of them has picked up something that you want before killing the Santa Slime.