Alright, well concrete overshoes I think is when the mob dips some guy's feet in cement, then drops him in the lake and he drowns. Lots of references to swimming, which makes me think water. Ulmo, maybe? Though it seems weird that Ulmo would drown.
Of course, there's always fishfleas (ditto on the Ulmo problem) and mecheteman's connection with aquatic chickens. Okay, so those two are stretching it a bit.
Also, OneFathom, since fathoms are used to measure the depth of water. Actually, that one seems pretty likely to me, since there's a lot about sinking/swimming.