If the player is using a weapon that deals more than 50 damage, such as a fresh Ham Bat, The player can kill a Jellyfish in one hit, meaning they will only take 5 damage without protection from the shock. Because eating a dead Jellyfish restores 10 Health, it means the player can gain 5 Health very easily. Because of how common Jellyfish are, it is a good tactic to restore Health fairly quickly.
Jellyfish are the only mobs that can cause direct health damage to the player while they are on a Boat.
Jellyfish are the only Shipwrecked-exclusive food that counts as both fish and monster.
Real life Jellyfish do not cause an electric shock. Instead, they inject poison to their victim on contact, which is described as feeling similar to electrocution.