Another way to drain rear diff fluid?

Smart.

Now, find a Dremel or a chisel and beat the collar back in enough to get a socket on it.
You're just asking for trouble using a wrench. Anything less than a 6-point and you're asking for more trouble.

 

I found a $40 rotary tool on Amazon last night, was able to get it for like $7 with some wizardry. Already got delivered this morning amazingly. Hopefully I'll have a positive update later today!

 

Take a flat head screw driver to that damaged area and hammer it out of the way. Loosen bolt. Nothing else to it.

 

Appreciate all the advice! I was able to grind away some of the bent lip and get a socket around the bolt like many suggested.

 

I would carefully file or grind away all of the bent lip. Then I would finish the job by cleaning the internal threads and install a new plug using a standard (i.e. not a deep-well), 1/2-inch, 6-point socket to fit. Lastly I would torque it to spec, and call it a day

 

Glad to hear you got it figured out. Good for you for learning to work on your own stuff. Down the road you'll look at this and laugh that it was an easy challenge.

 

Mine looks similar to this from off roading everytime I want to change my diff fluid.

I use a dremel to remove the peened over bit of metal that's preventing a socket from getting in there.
It takes less than a minute.