That negative charge is the formal charge on the carbon atom - the carbon atom that bears the lone pair. Keep in mind that the carbon also has a C-H bond (not shown), so the carbon has three bonds (one to the carbon chain, one to oxygen, one to hydrogen) and a lone pair. That gives it a formal charge of -1.
At 5.05 time stamp, why negative charge came near lone pair???
That negative charge is the formal charge on the carbon atom - the carbon atom that bears the lone pair. Keep in mind that the carbon also has a C-H bond (not shown), so the carbon has three bonds (one to the carbon chain, one to oxygen, one to hydrogen) and a lone pair. That gives it a formal charge of -1.