Never heard of mood moss.
That is emersed growth and it looks like fissidens to me, but I have never had it emersed grown, only submersed. It does look different underwater, it gets more dark green for sure.
But I am not sure of it, I will look for Mood Moss in a search.
IDK, mood moss for decorations in landscaping and banzai tree's and terrariums, some of that they are selling is dried and dead or fake. IDK if I would say this is mood moss, even though it looks a little closer to it, I still think it is an emersed versiion of A fissidens. Keep in mind that Phoenix moss is Fissidens Font. One of many fissidens out there, one of many from the US. Of course as I stated before, I am not 100% and if someone knows for sure, I am all for finding out a proper ID. I really just threw out the Fissidens to give you the whole name when Ron came up only with "Fissin", and Phoenix Moss since it is one of the more common.
If you found it outside, it could be ANYTHING. There are hundreds of mosses that could be found in whatever part of the world you are in. I've tried a couple of different terrestrial mosses in my tank and they did adapt and grow (after some time and acclimation) , but they weren't much to look at.
Truely the only way to tell what it will do submersed is to try it out. If it all turns brown and looks dead, give it another week to see if submerged growth starts appearing. That was my experience with both that I tried.
Thats exactly what i'll do. It doesn't matter if it does not look great for a while. It's in an external natural tank I use mostly to propagate plants. I'll give it a few weeks and if there is new growth, it would be interesting to see how it looks, if it can form carpetted growth etc.