slime (creature)
A common enemy in many RPGs. Usually represented as a blob, possibly with eyes. Sometimes, it is depicted with a core, which functions similarly to the brain/heart.
It usually has the ability to melt and digest its victim's body. Because of this, it became a popular monster in JRPGs and fantasy stories, especially the Dragon Quest series.
Similar to tentacles, slimes are common monsters in NSFW works, partly due to its corrosive properties being used to melt the clothes instead, and partly as a measure to avoid censorship.
For slime as a substance or with tentacles, see slime (substance).