Large voltage/amperage battery issues
The amp meter has ideally a zero internal resistance, so when you connect it directly without anything in series you're basically shorting the battery. Hence the high current reading. Since you have a high current the wires get hot because of all the power they are dissipating.

Best case scenario, you're battery simply need to be recharged.
I wouldn't be surprised if it was damaged though. Maybe somebody with more experience on batteries can add on that.

As a general rule, remember that an amp meter always goes in series with the component which current you want to measure. If nothing else is there, you will short the circuit.