wants to start by itself with no key in?

[baja1]

having thanksgiving dinner and wife hears a clicking sound coming from parked 2000 4cyl, go to investigate and engine starts turning over! doesn't start and now has a dead battery. I had replaced the ignition switch 5 years ago......is this thing possessed? where to look? gracias

 

[LittleCaesar]

Ignition switch OEM? My brother put an aftermarket one in our grandmother’s Buick years ago and it would stay cranked.

Test light handy?