Hello there.

[DrunkenMonkey37]

Whats it mean when you put your hydrometer in your brew you come back to it, and it's starting fist fights with the cutlery? ;P no. i mean it it went from 1010 then upto 1020, (i had to take a phone call from mi' mum, about 15 minutesish i was away)

 

[Coalminer]

The CO2 in the sample is coming out of solution and attaching to the hydrometer and making it lighter
BTW I hope you don't mean into the whole brew rather than just a sample