They have a built in distress call, so if you attack it'll yell for help and like Every Single Ocean Creature will run to the rescue.

To the ammonites rescue, not to yours.

Basically the equivalent of the chicken in Skyrim, you hit it be ready for a big fight with the town

This thing is a crybaby. Hit it, and it'll go blubbering to all its friends. Exactly who are its friends? The whole ocean.

Clear out the area before attacking. If you don't a lot of things will get swarmed. It's better just to take them out 1 by 1.