Let me tell the tale of the anus eating Bug.
The anus eating Bug, calling it the Anuseathupleua, or Arthupleuna, is a dangerous beast.
It doesn't eat anus at all!
It eats Broth of Englightenment!
No drinking it, no sir.
So now go tame,
This stupid worm!
On the artifact cave on the island near rock island. ( Artifact of the hunter) they spawn on land and in water. When they spawn in water you can go in the water and tame them they are passive in the water.
Easiest and safest way to tame this is to lure it under water. They stop aggro and you can tame as you please. Just make sure you come up for air every once in a while. Also be sure the water is deep enough.
For those of you who play pve on official just heads up you will need to tame this guys old school since you can't pick them up with crab/megas, since you may not be able to get them to water so they stay still here's how you do it. Full ghillie and bug repellent make sure you aggro them then bring them to a spot away from other wild dinos (preferably with a drake) wait till deaggro follow them from their tail side don't get infront of their head wait till they stop moving they will stand still for a few seconds then in that instant run to them aim for their head and feed the broth of enlightenment make sure you spam triangle/E if you missed they will raise their heads and attack go away deaggro and try again I tamed 4 last night this way good luck!!
So there's been mixed information regarding their stealth ability, at least in mobile.
Here's what I have found.
DO NOT REVIVE TAME.
Wild or tame, death removes their stealth ability.
If you're looking to tame, do so without killing it.
Bait it into watervif you can as they will deaggro.
If you have one tamed and it dies for what ever reason, don't use them in caves. You will be attacked.
I believe the same thing applies with the spiders.