strange bug!

i found this bug dead so i thought it's a good object for blip (i actually was looking for some tiny creatures to try some macro shots!)

i have seen these bugs since i was a kid. but i never got its name! it's a weird bug! and mostly lives under stones and wet places!

its length was about 2 centimeters (or less)!
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UPDATE: check this for a complete info about this bug. (thanks MissU2 for the link!)