I don't know much about relativity, so I hope my question doesn't seem ridiculous.
From the equivalence of mass and energy we know that a moving object looks heavier from an observer's point of view. It means the object looks remarkably denser at high speeds. Relativistically, is it possible for an observer to see the object as a black hole (something from which even light can't escape)? Of course, this conclusion is paradoxical since there are observers that see it lighter and less dense. Where am I going wrong?
