To dream of slime represents feelings about a situation being completely uninteresting to be involved with at all. Feeling that the simple thought of something disgusts you or makes you uneasy. Feelings about people or situations that you can't trust. A strong dislike of of something that may be difficult and unpleasant to remove from your life.
Example: A woman dreamed of stepping in green slime. In waking life she was jealous of the possibility that she was ruining her life after accidentally getting pregnant with a her third child with man she wasn't planning on keeping a relationship with. The green slime she stepped may have reflected her feelings about the man she had sex with getting her pregnant when she wasn't really attracted to him to enough to have a long-term relationship with him.
Example 2: A man dreamed of seeing a slimy slug. In waking life he had a very untrustworthy view of someone who wanted something from him for free. The slime may have reflected his strong dislike of giving away free stuff to someone he thought was using him because it may set a precedent that may be difficult to reverse without looking bad.