If you see blood on stage, then chances are, it got there courtesy of a burst blood packet. 

These contraptions are like ketchup pouches filled with (presumably??) fake blood that an actor will explode on cue all over their person; discarding the packet remnants out of sight is key to upholding the gory illusion.

Except in the case of the current revival of The Pillowman, now on the West End. 

Spoilers, ahoy! 

At the end of the play, Katurian is executed with a black bag draped over her cranium. As soon as the gunshots ring out, Lily Allen flails her arms against her bagged dome, combusting the blood packets therein. A few minutes later, she removes the hood to perform one final monologue, revealing the bloody mess inside.

Now, this moment self-evidently leaves behind our customary corporeal reality, befitting The Pillowman’s fictional story about how storytelling blurs together fact and fiction, the mortal immortality of the author, and the fuzzy line between illusory violence and real violence — all of which are themes that could be related to the decision to let the audience plainly see these blood packets.

OR, if you’re sitting far enough away from the stage, these pouches might actually look like beheaded chunks of Katurian’s brain and skull, seeping from the headshots.

Which is an image that’s both anatomically accurate and thematically apt; grotesque parts of the character’s mind spilling onto the stage through carnage can operate as a visual metaphor for the nature of Katurian’s gruesome storytelling, scalped out of the sadistic recesses of her consciousness.

These blood packets could also represent what Katurian cares about most, the products of and from her brain left behind on this earthly realm: her stories. The detritus of the blood packets are joined on stage by the figurative detritus of Katurian’s brain: the pages upon which her stories are printed. At play’s end, both the blood packets and these only remaining copies of her stories are left scattered on the ground, laying in wait to be picked up in and by the future.

Or, they will stay on the ground forever, the forgotten trash of the past.