According to the Wikipedia article on Slime mold :
"Professor John Tyler Bonner, who has spent a lifetime studying slime moulds argues that Slime molds are "no more than a bag of amoebae encased in a thin slime sheath, yet they manage to have various behaviors that are equal to those of animals who possess muscles and nerves with ganglia -- that is, simple brains.""
See also the videos ohn Bonner's slime mold movies ", Slime mold form a map of the Tokyo-area railway system and Rebuilding Iberian motorways with slime mould .
Carl Zimmer wonders Can Answers to Evolution Be Found in Slime?. See also his post .