I am not a physicist either so this is just my opinion. A black hole made from a single star (around at least 8 solar masses) actually should have less mass than the star that created it due to the supernova blowing the outer layers of the progenitor apart. So, unless the star directly collapsed, an unnova, it will be less massive at first. However, close to the singularity will have crazy physics because the mass that collapsed, and we're talking about something like 4 solar masses for the singularity, still has all that gravity but very little "surface area." Think of a female ice skater twirling with her arms outstretched and her hands clenched in fists. With her arms fully extended, she spins slowly. As she pulls her arms in, she spins faster due to conservation of momentum. If you walked into her reach with her arms outstretched you would get punched maybe once a second. If you did the same thing when she had her arms pulled in you could get punched 10 times a second. The strength of the punches hasn't really increased, but the frequency has, so the damage goes up. A black hole is like that ice skater with her arms pulled in: all that gravitational effect is in a much smaller area than before so once you get close enough it all hits you at once.