Images and observations by Loriann Gross, who asked me to help ID.
"...we have them every morning around the house, I sweep up a big pile every afternoon when I get home from work at least 50 everyday, down at the house at the beginning of Mienars Road they have hundreds of them, they seem to die all on their own and they leave an oil mark everywhere they are..."
Was laying on sidewalk close to sunset. Slithered away into a marshy area