a question (old-timers, look-a-here!)

[knen]

Since there seems to be a great hell's kitchen presence on this board, I tough I'd ask this history trivia question: What on earth is that molten metal thing on the hudson river around 57th street? I always like to say it's something that washed up from Coney Island (the days of the super dangerous rides) but there must be a real story too. Anyone know it? Thanks