It appears that you seem you have an Iraqi Camel Spider living under you bed:
And given that they move at 10mph, you'll see him come an go before you can bat an eyelash. So no need to worry, for you won't see a thing.
Oh, and in the likely event that the mischevious fellow chomps and bites, simply wait for the cyst of the bite lump to rupture, pack it in with gauze & antibiotics (for it's too large to stitch you see), and wait for 4-6 weeks. When all's said and done, you'll be the proud owner of your very own penny sized scar! No, no my friend - there's no need to thank me...just thank the brave men and women of the US Army deployed in Iraq.
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"Camel Spiders - things that make you go 'noooo'!"
"NOOOOOOOOOO!"