First Appearance: Hvs.tCF 83
Real World References
House elf, or -gnome is an Nordic mythical creature, who lives in a human house and either helps or punishes the humans, depending on how it is treated.
Harry Potter book and film series also has house-elves, magical slave creatures, that look like shaved rats.
House Elves likely references the TV show 'House', featuring the medical doctor Gregory House and his colleagues and patients.