Yours is a very interesting problem. I spent most of my career in instrumention of some sort and don’t remember ever seeing it. The gauge needle is going full tilt to both pegs and very quickly at that. This makes me think that you might have a ‘dirty’ supply voltage if the truck was running.
I would troubleshoot the problem by first disconnecting the sender wire at the gauge. With key on, if the problem goes away you know where to start looking. If it stays, I would remove the (+) side wire and use a battery charger clipped to the (+) side of gauge and negative side of charger to gauge housing. If problem is gone then it’s in your voltage supply wire or gauge ground. If it stays then your in the market for a new gauge. Good luck

Six volt guy living in a twelve volt world