Sharquoi

"Q: What's a Sharquoi?"

- Press

"A: Very freaking dangerous."

- Frank O'Connor

The Sharquoi is in the Conversations from the Universe booklet found in Halo 2: Limited Collector's Edition.

Background
Although it's listed as deleted content here, as of 2008 the Sharquoi has never been confirmed as deleted content by Bungie; it may actually be part of a story still in planning or production.

This has been speculated to be another Covenant race. In a deleted scene, a mural can be seen showcasing the Covenant races, including a very large creature believed by some to be a Sharquoi. However, this creature could also be a Drinol, which may or may not have been cut at that stage of development. There is also a possibility that Sharquoi is the Covenant word for Drinol, although the name Drinol does not follow the same patterns of all the other human names.

It is also mentioned in Conversations between two Sangheili discussing why the humans don't join the Covenant, implying it to be some sort of weapon or otherwise; "I suspect we are forcing them (the humans) into a tighter arena than they care to fight in - soon we may be able to use the Sharquoi."

The Sharquoi could also be something other than a species. Due to the chronology of the conversation (between Halo and Halo 2), it could be a Covenant term for Scarabs; although this leaves it unclear why they weren't able to use them before. It could be a certain strategy or weapon that can only be used in cases where the enemy is getting beaten back to their home planet.

Unlike most of the elements listed as deleted content here, the existence of something called the Sharquoi is known to be part of the canon Halo universe, thanks to its mention in Conversations.