World's End Publishing (This Is Not A Test) has produced an enticing supplement called Broken Vaults, underground missions. ("A few feet of concrete and steel, and a ton of packed earth. They thought it would be enough. They were wrong." -Horatio Allen, Wasteland Historian)
The supplement has a number of vault creatures including three slime/ooze types, which are awesome. I found several STL files to make some of the models on my printer. I considered using some homemade slime from by 8-year-old granddaughter's collection However, there is a puzzler about how to paint the Engulfing Ooze. This creature is nearly invisible to the naked eye unless it is ingesting a prior victim. Painting choices for something nearly invisible are curious. Black? Gray? Rainbow? Probably going with my deepest gray. It is a puzzler.
BTW, I cheered for The Blob in the young Steve McQueen movie.