Plectranthus ornatus (Coleus canina) is a South African sub-shrubby perennial with slightly succulent leaves. It comes from the same sort of semi-desert habitat as many Pelargoniums ("Geraniums") and has evolved the same defence against browsing animals by producing foul smelling leaves full of volatile oils.

It is used as a summer pot plant outdoors for it's alleged properties to repel cats away from areas it's planted though I doubt the effectiveness. The cat would have to physically brush past it to release the smell and would just avoid it if it wanted to anyway.

Grow it for the attractive blue, vaguely Salvia-like flowers that are produced in terminal spikes in late summer rather than for repelling cats. Either take cuttings to overwinter indoors, or bring the parent plant inside for the winter.