"It required a few stitches," Darby told Entertainment Weekly about his injury sustained while shooting the scene.
"But now I've got a nice little scar to remind me of The X-Files. The guy stitched it up with a couple of little x's ... It all makes sense."
The episode, due to screen here on TV2 on Thursday at 8.30pm, is called Mulder and Scully Meet the Were-Monster, a play on Darby's role as a werewolf in Taika Waititi's recent film What We Do in the Shadows.
Darby told EW his time on The X-Files was a dream come true.