A melanistic leopard can look almost completely black from a distance. Get the light and angle right, though, and something wonderful appears: the pattern is still there.
Ghost rosettes
The rosettes remain visible beneath the darker pigmentation. They can appear like a secret pattern waiting for the light to reveal it.
Black is a colour variation, not a different species
The animal is still a Sri Lankan leopard, Panthera pardus kotiya. The darker coat is a pigmentation trait.
Wild bit: the spots never really disappear.