Puffer fish self defence

The Puffer Fish, or Blowfish blows itself up to defend
itself against its enemies. When it is threatened, the
Puffer Fish will turn itself into a large ball covered with
sharp spines. Hopefully, the enemy is unable to swallow
the inedible ball and swims off.

Almost all Puffer Fish contain a toxin called

tetrodotoxin, which is foul tasting and often lethal
to fish. To humans, tetrodotoxin is 1,200 times more
poisonous than cyanide. There is enough toxin in one
Puffer Fish to kill 30 adult humans, and an antidote
does not exist.

Be careful.