The following is a Taxonomy of Desert Arthopods, a list containing all the Bugs of the Desert.
Particularly, these concern the desert multiplayer map, The Crystal Crusade.
Class: Insecta & Arachnida
The "invisible scorpions" are a common sight in the desert area. These scorpions are often found ambushing prey at chests. When traveling in a group of people, these scorpions will make themselves invisible to all impatient members of the party. The science behind how they do this is unknown, but it's known that only the patient may hope to catch a glimpse of these majestic 6-legged beasts.
The scorpions that guard the first chest will not spawn properly if you open it while members of your party are still loading in, and can only be seen/attacked by those loading members. To prevent this bug, wait for everyone to load in from the basement before heading to the chest (wait for everyone to move). If you accidentally trigger this bug, you can go back down to the basement, and back up to see the scorpions again.
While they look like normal boars, they are actually Arthopoda, bugs. The "unapproachable boars" are an uncommon sight to behold in the deserts of Titan. They are often companions for the bow-wielding bandits of the Untouched City, and are used to guard their chests. The shards covering these boars are actually group-detecting antennae. If they sense that a group is not sticking together, they release a pheromone that afflicts everyone in the group with a terrible case of social awkwardness, making the boars completely unapproachable.
The boars that guard the second chest will not spawn properly if you open it while members of your party are still loading in or disconnected, and can only be seen/attacked by the disconnected/loading party member(s). To prevent this bug, wait for everyone to load in from the basement before heading to the cutscene with the ranger (wait for everyone to move), and additionally make sure nobody is disconnected. If you accidentally trigger this bug, you can go back down to the basement, and back up to join in the glorious slaughter of boar and man.