What is that on my Dwarf Red Tip Hermit Crab?

[Pysiek]

I just get these last night. What is that "eye" looking thing on the back of shell?

 

[Salty B]

Looks like a barnacle to me.

 

[Marinne13]

barnacle like Salty B said...harmless

 

[Pysiek]

So I don't have to worry about it?

 

[Marinne13]

Nope, its just a filter feeder and it may not even be alive...barnacles have a hard time living in captivity

There is usually a feather like object that comes out, YouTube them

 

[bjohanson1234]

Could also be a limpet
If it just suddenly appeared, and is moving, I would believe it is that. Also harmless.

 

[Aquarian]

+1 Bjohanson that is a limpet.

 

[Pysiek]

I do see feathers coming out of there

 

[ErinCahir]

Feathers = barnacle. Or other filter feeder.