Id this worm?...or....hmm well i dont know what to call it.

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This thing has been growing in size pretty quick. Has webs or strings he lets out, traps food etc and reels it in, kind of unsightly all these webs all over everything. Any idea what it is? Or maybe how to move it, seems to be in a hard shell. Or just leave it alone. Thanks. I didnt really know how to look this one up as I havent really come across it yet and well dont know how to categorize it. Thanks.