For anyone who is planning on taking a beach trip, you might want to be cautious of the water if you see any seaweed on shore – some might contain flesh-eating bacteria. The colossal seaweed blob, drifting from the Atlantic Ocean, is starting to show up on some Florida beaches. Researchers say it could stick around for months. The clumps of brown seaweed, also called sargassum, are part of a massive bloom collecting in the Caribbean Sea spanning nearly 5,000 miles.