The late Dr 
His journal was an elaborate testament, divided in several volumes: some were destroyed by his own hand, some were recovered, and some are still lost to this day. In the cellar beneath a burned cottage, where the doctor spent his last years in almost-constant delirium, a tattered volume was found.
In one particular page, there was a disturbing portrait with no explanation or citing whatsoever accompanying the sketch. Was this the depiction of a malevolent demon's face, summoned by the doctor to do his bidding? Or a visitor from otherworldly dimensions, bearing forbidden knowledge that pushed the doctor's sanity beyond its limits?
We reproduce this picture, asking for the reader's discretion when theorycrafting in the comments below. Thank you.
@nyarlathotep