#1 for me is the survival tool between my ears.
#2 would be a sharpened object (stick, rock, RSK, your choice)
#3 Mr. John Browning's finest creation, the M1911A1 in the variation/clone of your choice.

All three items have saved my posterior at least once, and are generally with me all the time.
_________________________
I do the things that I must, and really regret, are unfortunately necessary.

RIP OBG