Reads like a dead short. The cable to the starter isn't fused so if it rubs up against something and wears away the insulation on the wire you will have completed a circuit that will not break and your battery will smoke itself trying to supply it. Could be an internal fault in the starter too. On the positive side your alternator is probably OK.

Anyone who doesn't believe in the power of batteries to start fires try dropping a watch battery in your pocket full of change. Damn that hurt...

'89 P'up, 2.6 I-Tec, 488,000 miles and done... gone to the great beyond