a. you can Dremel a slot in the stud, and try using a flat blade bit in an impact wrench to extract...
b. drill a small hole in the stud about an eighth to a quarter inch deep,.. and hammer a torx head bit into the hole,.. then twist it out, or use an impact wrench on it...
c. try the lefty bit, and extractor...
...ehh... what do I know...
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