Please help identify these organisms

Please help identify these organisms

Observation - Please help identify these organisms - Southern Africa. Description: Length of organism corresponds to the length of a finger nail. Its width is roughly half the width of a finger nail. Its head (which is long and thin) can retract completely into its body (which is a flat, oval shape, and roughly six times longer than its

Length of organism corresponds to the length of a finger nail. Its width is roughly half the width of a finger nail. Its head (which is long and thin) can retract completely into its body (which is a flat, oval shape, and roughly six times longer than its head). Propels itself forward by some kind of suckers on its head. Can stay in one position for days at a time.