How one man created his own universe

Replacing the sun with a supermassive black hole only to see everything from Mercury to random Kuiper Belt objects get sucked into its gargantuan mass is indeed rather satisfying, although it does remind us of Universe Sandbox's sometimes cunning methodology.

A Black Hole in this case is a huge star with enormous gravity rather than a new object with different properties. Rings around planets are simulated by weightless, collision-free particles rather than fully simulated microscopic chunks of ice.