Which feature distinguishes slime molds from fungi?

The right answer is Slime molds are able to move

Mucilaginous mold are characterized because at some stage of their life cycle they form multinucleated aggregates (plasmodia) or multicellular (pseudoplasmodiums) that slide along the ground feeding on decaying plant matter. A few are parasites. They can be found on the ground, on the lawn and in deciduous forests. They are also common in leaf mulch or even in silt that accumulates in gutters. Some are aquatic, freshwater or marine.

The "body" of these Myxomycete consists of a mass of cytoplasm called plasmodium which is surrounded only by a thin membrane; there is no rigid wall like most mushrooms. This is why the plasmode can move by creeping or flowing, that is to say, by amoeboid movements.