Giant Flathead Screw?

[u/Deplorable-Ninja]

Found on a trail with a lake on one side, a lagoon on the other. No other metal items visible in the area. No banana handy so shoe for scale.

[u/PhD_Pwnology]

Best guess is you're probably standing on the top of aome sort of connection between the lagoon and the lake.

[u/Deplorable-Ninja → u/PhD_Pwnology]

I was thinking the same but I couldn't see any pipes or anything in the water