There is tons of scenario regarding this however one of the most possible scenario when BTC hit $100 will be that there will be alot of people jumping the ship and proclaim that BTC is dead , which in most scenarios had happened before. This will then be followed as alot more sell pressure that keep on driving the price to ground floor .
Worst possible thing after that would be sell pressure will keep ongoing until the rage and fuss stopped and the best scenario would be that someone / the chinese ASIC manufacturer would put up a huge buy wall to prevent it from going deeper as that may only hurt their business ( part of my speculation which you can check from the previous pages ) , this is unlikely to happen but still possible to happen


The bolded part should be added with "yet" , things might change in the future as everything keeps going better and better