What fungus?
Sounds like its high on psilocybin.

Barksnails

Although there is not a snail book for the Garden Route, from the field guide to the eastern S Afr, we can glean.
3 groups of Barksnail, group one with a keel

Of these:
Edouardia carinifera Keel Barksnail: Knysna eastwards - lives on leaves and has a relatively clean shell, rare (i.e. low densities) in forest margins;
Edouardia aerinicola Doubleband Barksnail: Mossel Bay eastwards - brown band beneath suture, foot grey with yellow sole, patchy dust coated shell - often bird-dropping like, branches and leaves and reeds, in a variety of habitats, common.

&

Edouardia dimera Bicolour Barksnail: also occurs from Tsitsikamma east, but does not have a keel, and is far more coated with bark; foot grey with dark brown sole: not likely.

Unfortunately, neither of the two keeled Barksnails looks a really good fit, so wont go to species ...