It does no harm and might be beneficial.....and there is nothing you can do about other than sort of rake it around.
Plant something in those empty mulch beds to hide the stuff.
What are you mulching if they are empty?
Linda C

Here is a link that might be useful: slime mold

AS lindac says, it's really rather beneficial; however if you can't stand the sight of it or worse - like it's by the front door and your MIL is coming to visit, and it hasn't turned brown/dry yet: you can make a mild mixture of 1/2 teaspoon liquid soap (not detergent) into 1 gallon of water and spray them. While slime molds come in different colors, sizes, and types, I expect yours is just as susceptible to being washed as my local versions. That is, once you gently spray or pour the soapy water over them, they will shrivel up and disappear in a couple days.