It does look like something that eats coral because these things often look like what they eat. And the more colorful and textured they are, it seems (at least to me) the more likely they are to prey on a specific coral (that they look like). Of course, that's not always true. In any event, if it is a coral eating slug and it doesn't find its prefered food soon, it will die. These things often don't live very long anyway though (even in the wild).