Wildlife Spotting

Found a female in same location last year. They seem to hunt on stationary objects in the water (stumps, rocks.. floaties) they have 1 long thick "string" to the shore. They are very spiky, the pictures don't show it all that well but they are more shape and pointy then any I've seen else where. I believe the spikes would let them walk on water, though I did not observe them doing so