My character's race is Nord. I was standing at the entrance of Blind Cliff Cave entrance then I took a swim in the river right in front of the cave in the direction of the current. Right after the first small waterfall there was an underwater chest with some items, amongst them was a piece of paper with the title "Ability: Fish Gills. Can swim underwater without drowning". And sure enough after opening the paper I had an active effect of water breathing. I looked it up online and found nothing about this possible hidden secret!

any comments are welcomed

http://cloud.steampowered.com/ugc/576701767853575989/A0760C881A20AACED2106C22C32AFA8DAE7BE467/

Map
http://cloud.steampowered.com/ugc/576701767854124251/7057F14FAFCA06D4ABD5DA489531ADBF3384A6D3/

Are you playing with any mods on?

yep 36 mods but almost all are graphical mods. I make sure to use mods that don't give my hero any special powers.

Where is this chest located?

My guess is one of them added this item.

If any are ESP/ESMs, you'll need to check them in a program that displays the data to make sure.

Also, it doesn't really fit the definition of an Easter egg to be honest.

I only have a couple of ESP but all of my ESP are either High resolution texture pack or Hybrid shaders

I will update with a map image

If it's an ESP/ESM, it can edit things besides graphics.

Texture replacers don't need ESP/ESM files. Beth just uses them to make distribution easier. That's why they frequently use dummy ESP/ESMs with BSAs

hmm, I guess you are right, I turned off all my mods and now I cant find that chest

even though these were my only .esp mods

HighResTExturePack01.esp
HighREsTexturePack02.esp
RCRN Classic -Hybrid Shaders.esp
RCRN Legacy - Hybrid Shaders.esp
RCRN Pure - Hybrid Shaders.esp