How does this jellyfish sting without touching you?

The video explains why upside-down jellyfish can sting even when not in direct contact. Scientists discovered that these jellyfish release toxin-filled mucus containing cassiosomes, which are balls of stinging cells. These cassiosomes can harm swimmers and kill prey like brine shrimp. The research team has also found cassiosomes in other jellyfish species closely related to the upside-down jellyfish.

What new insight or understanding did you gain from this video?