This link summarizes research showing that slime moulds can find the shortest path through a maze, and thus demonstrate a primitive form of intelligence. I find this interesting, but remain a bit skeptical that it can properly be called intelligent behavior.
That is not intelligence. It grew everywhere, and survived preferentially in the route which utilized food the most efficiently. If it grew through the maze in the first place in an other than random way, that would be intelligence.
I used to work for the government, and several of my co-workers exhibited the same level of intelligence.
It has to find the food first, before it can develop the most efficient path that joins them.
It didn’t find the food at all: the slime was seeded over the entire surface of the maze, then the food was introduced at 2 corners.