why did my record player slow down, speed up, then go back to normal?


why did my record player slow down, speed up, then go back to normal? it all happened within maybe 12 seconds. it slowed down, then sped up immensely, then went back to normal speed. why?
leemurray2007
@stereo5 thanks for the tip! i'm going to do that, even if the belt isn't the problem. (it probably is, but then again, it only happened once for about 30 seconds.)
@atmasphere thanks. this is an older turntable, but it has electronic speed buttons (33, 45 rpm). I think i'll check the buttons for corrosion.
i guess it could have been a power surge from what everyone is saying. It might've been the belt, but it had never happened before or since. 
@millercarbon 

man you are funny! you have kept on talking about aliens throughout the post. i don't care if you keep going, i like having you around.
Didn’t spend enough on your cables and contact cleaner; )
is it belt drive? Did the belt ride down on a crowned pulley possibly?