The jellyfish indicates deceptive people or situations in your waking life. You should be aware of everything, because it doesnt mean that whatever you like is good for you, it could be completely different.
Dream dictionary: Jellyfish dream meanings
To see a jellyfish in a dream represents some painful memories. It can also mean a hidden aggression to a certain person or an unpleasant situation.
If you see a jellyfish in a dream, then such dream foretells about your negative past. Perhaps there are some hidden anger you were unable to express, therefore you are dreaming about it. There is also a possibility that you feel some kind of anger towards particular person in your waking life. On the other hand, the dream indicates the lack of self-trust you are suffering from.
Obstacles and disappointments and if it stings us we will be deceived.