Many times when a star grows old and the nuclear reaction within becomes too weak to push back against the force of its own gravity, it collapses in on itself and forms a black hole, a hole in the fabric of space which not even light can escape from at close range. When sucked into one, you will either (a.) be transported to another time and/or universe, (b.) be crushed and stretched by spaghettification, or (c.) be stuck drifting through forever. Options a. and b. are the most likely, but you are still best off avoiding them.
Miniaturized, harmless artificial blach holes to hold large cargo are now available at millions of Galabucks.