Well... My pass rear brake caliper was occasionally seizing. I knew brake fluid was overdue, which I had in my mind, just never had time.
So last night, I prepared brake fluid flush.

Lifted the car, removed all wheels, remove as mush brake fluid from reservoir, filled with new fluid, connected pressure bleeder. Everything is set.

Pass rear, which is the furthest from master cylinder, connect hose and wrench to bleeder.
Tried to unscrew bleeder... no go. Tried little harder.... snap... ha...... skip this side for now and move on to other calipers.

All other bleeders are free. Except the problematic pass rear caliper.
Well.... since the broken bleeder is not leaking, I guess I need to get new remanufactured caliper. sigh....