Alocasia? Colocasia? A photo showing the whole leaf (and one showing the whole plant) would be better.
Best guess is Colocasia 'Black Magic' or one of its closely related cultivars. A whole leaf and the whole plant would go a really long way to helping us ID, because there are also Caladiums, Xanthosoma, Philodendrons and some Anthuriums with that type of primary venation.