this is a mind trick, the picture is made in such a way to give the illusion of multiple feet and legs... the more you look at it, the less it makes sense, your brain tries and make sense of it, but it can't. But that's when you focus on it's legs.
go by how many feet there are, there can't be more legs than feet, and there are 5 feet, so we can assume that it has 5 legs, it's a simple optical illusion really.
^it's just the shading on the picture, it's in the spots where the legs SHOULD be, because that it what your brain is used to seeing, BUT the feet are in a different area, your brain attempts to connect the two, and can't make sense of it, so it makes you see multiple legs. But instead of looking at the elephant as a whole, just look at it's feet, on at a time, there are five feet, and five legs. You just need to dicpher the illusion