If someone with 100,000 or more dropped them all at once, btc would be pennies.
at the moment it would take about 600,000 BTC for btc be pennies, but this is not true, because if someone start selling those amounts, would rise quickly big bid walls that would slow the fall.
Considering that is one market order only existing bids are considered. It would bounce, for sure but it would get there if only for a moment.