heh, I just dug one of those out of the scrap bucket and epoxied it into a drain plug in my truck that I finished rounding out in spectacular fashion.

I wasn't the asshole who started rounding it, but I sure was the asshole that finished the job. Replacement with an actual hex head on it is sitting on the workbench. No more water trap woes if the cheap hex wrench stays glued in that fucked up part

edit: it worked great. The plug had dielectric corrosion (steel plug in a mag/alum body) and at first I thought I just tightened it up too much but nope, I felt that rust break, saw the removal of material on the plug itself once it was all the way out, and I'm sure it's in the secondary fuel filter now. Replaced with a brass plug that had a 19mm hex head on it so no more worries. Big wrench, little torque kinda thing - it's the o-ring that makes the seal, not the torque.