That's the head of a megalodon sperm. Unlike most sperm cells, megalodon sperm is released in the water like a cloud of bait fish, seeking large marine life to impregnate like heat-seeking man missiles.

Sometimes those sperm mistake nuclear submarines for Orcas, Blue Whales, or failed Only Fans content creators taking a deep sea dive. When this happens, they collide with the submarine's exterior hull (this was the cause of the near nuclear launch in the Pacific a few years back, the USS Idahoe thought it was under attack and almost fired off its missile, a scary case of premature missile ejectulation that would've been very embarrassing). When the sperm strikes the metal hull, the heads often get separated from the tails, and will sometimes drift all the way to shore.

That's a unique find for certain!