Effluxers are fork-like objects that are used to ward off ogres.
Official Description[]
These silver forklike gadgets are stuck into the ground in order to provide a measure of protection from the ogres. When triggered, effluxers release a cloud of scent that damages ogres' sinuses (and isn't particularly pleasant for any nearby elves).
Unofficial Description[]
It would seem appropriate to add that Keefe Sencen uses Effluxers to prank his least favorite elves. Effluxers have been found in several of his supply stashes around Candleshade, and in Exile, he tries to hide them where Dame Alina will trigger them.
History[]
Book 3: Everblaze[]
Lady Cadence has Sophie, Keefe, Stina and other prodigies plant them around Foxfire's grounds during detention.
Effluxers were placed outside the Sanctuary, to protect the creatures living inside from ogres.
Quotes[]
“...this is an effluxer—also known as an ogre repeller. One of my favorite inventions you guys make, by the way.”