Oslaka is the name of a Geisterdame (or as she has been nicknamed, a Geisterdamsel) whom Othar Tryggvassen, Gentleman Adventurer, met in Paris after she was killed in a fire. According to his accounts, they lived connubially until her natural death recurred.

Due to the temporal instability in Othar's story, there is considerable question about whether Oslaka actually ever existed. However, his account of how he inferred she survived in Paris, and how she reacted to the outside world sheds some interesting light on Geisterdamen psychology.