The Horrorterrors are outer gods in Homestuck that dwell within the infinite void between universes, known as the Furthest Ring. Very little is known of them, however they appear to have some of hierarchy with the smaller gods at the bottom who serve the middling gods who in turn serve the Noble Circle of Horrorterrors. The horrorterrors are known to whisper to Sburb players who dream on Derse to assist them, make deals with them, and even request the players' assistance. Some humans were known to have been psychically exposed to the horrorterrors, in order to cope with this exposure they reimaginined them in a friendly form which would eventually form the basis of the children's TV show, Squiddles! Possibly due exposure amongst more members of humanity, rumors started that the show was secret occult propaganda, though this appears to have been entirely unintentional on behalf of the horrorterrors.
Due to the nature of time in the Furthest Ring it is likely no chronological order of events can properly describe their history, however at some point Lord English begun slaughtering them, it is unknown it this was purposeful or a side-result of English destroying the dream bubbles, due to this they contacted players asking for help. At some Feferi Peixes, who was raised by their emissary, Gl'bgolyb, convinced the horrorterrors to create a series of stable dream bubbles, which allowed players who had died to communicate with players who had lost one of their bodies. However Vriska Serket believed the horrorterrors willingness to create the bubbles was due to them serving as a distraction for English and thus temporarily sparing them from being slaughtered.