What is this?
 

What is this thing in the tube? It keeps spraying out spiderwebs type of things

vermetid snail

+1

They're generally harmless except that they can successfully reproduce inside aquariums and that snotty stuff they send out irritates the heck out of corals if it's constantly landing on them. I generally try to kill any that pop up in my tank by either epoxying over the opening of it's shell, or using one of my pointy fragging tools to skewer it.

Thank you very much. I will try to kill the bugger