Complex sentence: There are around 30 records of humans killed by a cone snail--the molluscs can attack if provoked and can sing through a wetsuit with their harpoon, which resembles a transparent needle.
Split into simpler sentences: There are around 30 records of humans killed by a cone snail. The molluscs can attack if provoked and can sting through a wetsuit with their harpoon, which resembles a transparent needle.