feather duster & slime

[fishguyxd]

I put in a new feather duster and it's been doing fine when today I looked and it looks like long cob webs flowing in the current from it, but when I pulled some(web stuff) out and it was exsposed out of water it was a thick clear slime anyone know wht this is ? the only thing that has been different is my emerald crab is real friendly & nibbling on the tube of the duster.