It's been about a month since I've started using my Anycubic i3 Mega and everything has been going great. But today, I left it alone to print a 3DBenchy and it suddenly stopped mid-print. I didn't see it stop but once I came to the printer, the motors and the bed were at ambient temperature suggesting that it has stopped for quite a while. I was surprised that the Bed Temperature registered at over 200 ºC (although it wasn't at all hot) and tried to stop the print. However. I wasn't able to stop the print (It said stop failed) and I couldn't change the temperature, so I just switched the PSU off.
Any ideas on what happened here? It was working fine for an entire month and was working fine for the day, but mid-print it just suddenly broke. I've also uploaded a GIF to Imgur to show how the bed temp fluctuates a lot. Any help would be appreciated :)