StillTrying beat me to it.
Don't use a current source as a load!!!
As he said, replace I1 with a 60 ohm resistor and it will all make sense.
I would also suggest putting V1 back the right way round then running a DC sweep with .dc V1 -12 12 instead of .tran 1ms, which will show you when the MOSFET's channel has enough gate voltage to take over from its body diode. (Not that simmed gate thresholds are to be trusted - there's far too much variation between batches of the same part.)