- "Beyond life there are'—his face grew ashen with terror—'things that I cannot distinguish. They move slowly through angles. They have no bodies, and they move slowly through outrageous angles...God, they are breaking through! They are breaking through! Smoke is pouring in from the corners of the wall. Their tongues—ahhh—"
- -Frank Belknap Long, The Hounds Of Tindalos
The Hounds of Tindalos are extra-dimensional predatory creatures, capable of materializing at any point in space and time to feed upon victims.
The Hounds of Tindalos are said to inhabit the "angles" of time; in contrast, humans and other earthly lifeforms live within the "curves" of time. Little is known about their appearance, as few victims survive their attacks; however, they are known to have hollow proboscises used for feeding, and are associated with a blue pus-like substance.
Hounds may appear wherever angles or corners may be found, especially those sharper than 120 degrees. When breaking through into the universe, their arrival is preceded by the appearance of smoke pouring from the corner, followed by their head and body.