Updated 13 July 2004, 11.08
The Marine Conservation Society want holidaymakers to report jellyfish sightings around Britain this summer.
They want to know how many of them there are and where they hang out most.
So, have YOU ever had a run-in with a jellyfish?
Perhaps you've been attacked - or stung/
And will you be doing your bit for the MCS while on your hols this summer?
Or will you be keeping your distance?!
Whatever your jellyfish story is, e-mail and let us know.
Unfortunately this topic is now closed but there are Comments pages on other subjects on the main Chat index.
I see jellyfish all the time at the beach where my gran stays and I see people kick them and poke them. It is totally disgusting.
Gillian, 14, Scotland
I'd freak out if I ever saw a jellyfish. I don't want to I've seen some in a zoo when I was tiny and I ran away crying!
Gina, 10, Bristol
Me and my friends went on a boat and sailed through a swarm. Of course the boat capsized and there was a huge doctor bill after that!
Naomi, 14, Atlanta USA
At Easter my mum, dad and sister went to downhill beach for the day and when we got there one side of the beach was completely crammed with people so we went to the other side and then we found out why everyone was on the other side, because the whole side was covered with dead jellyfish. I never want to see another jellyfish as long as I live.
Jennifer, 12, Larne
We were watching the America's Cup and we decided to dive off the boat and go swimming. Suddenly I kicked something extra squish and began panicking. It was a jellyfish! Luckily I wasn't stung.
May-Lee, 14, New Zealand
Every year when we went to France when I was younger there were always huge dead jellyfishes lying on the beaches. My dad would prod one with his toe and it wobbled! Disgusting!
Emily, 12, Surrey
I was stung by a jellyfish once when I went for a swim in Brighton! I came out of the sea and there were loads of stings on my feet. It didn't hurt as much has I thought it would though!
Sam, 11, Portslade
Once when I was about five, I dragged a jelly fish out of the water and began stamping and poking it! It was a wonder I never got stung!
Marlene, 12, Belfast
I often go surfing and body boarding in north Devon and there are 100's of jellyfish on the beaches and in the water there, but they're not very big.
Alex, 14, Exeter
I like jellyfish 'cos they have never harmed me or anyone I know.
Matthew, 11, Slough
I see lots of jellyfish. Only the tentacles sting you - I pick them up by their body, the little pink or blue ones don't sting you. I saw one like a cauliflower and one that was an Atlantic jellyfish which kills you if you get stung.
Kirsty, 9, Eastleigh
We were on holiday and there were millions of dead jellyfish... Me and my cousin didn't go in the sea after that!
Nicky, 12, Crawley
Yes I have been stung before - twice when I was 5 in Cornwall. The jellyfish was huge! I got stung under my arm. The other time when I was 8 in America it was a small one and I got stung on my hand, but I'm not afraid of them!
Jodie, 12, Hertfordshire
When I go to Wales on holiday I find dead jellyfishes on the beach all the time. Sometimes people poke them with sticks. It's gross
Rhian, 11, Maidenhead
YES!! They were all over the beach in Spain! My dad and sister were throwing them at me! eww!
Megan, 14, Huddersfield
Once in Devon I was running along the beach when my sister fell on something slippery, it turned out it was a HUGE dead jelly fish, about as big as my head and a half! But in the end my sister didn't get injured, so the jellyfish saved the day.
Charlotte, 12, London
I went to a beach in Blackpool once and was playing catch with my sister, I slipped on a jellyfish bare-footed! It was really disgusting!
Layla, 12, West London
My step mum went canoeing through a swarm of jellyfish.
Of course, she fell out.
Alex, 14, Epsom
When I was little my mum and dad and me went to a beach bar on our way to the hotel. At one side of the beach it was covered in dead jellyfish. Fortunately we were on the other side of the beach so it didn't effect us. I don't wish to ever see a live jellyfish though!
Casey, 10, Kirkby
We used to have loads of dead jellyfish on the beach when we went on holiday. People used to kick them and throw them around... it was horrible!!! I get stung a lot when I go swimming in the sea. It happens without you even knowing it!!! You come out from the sea with all these stings all over your feet!!! Luckily they aren't harmful, they just hurt a lot!!!
Louise, 13, Birmingham
I see them all over the beach near my gran's. The whole beach is littered by the jellyfish.
Maria, 9, Liverpool
No but I got stung by a weaver fish once it was horrible! My leg was numb with pain for about two hours!!!
Lucy, 13, Hampshire
When I was young my dad took me to the beach to see some rare jellyfish which had migrated there or something, I can't remember that well. There were hundreds of them, they were pink and they were huge!
Anna, 10, Ayrshire
No and I wouldn't want to but I find them fascinating! Did you know that jellyfish are 70% water - and they can still be a serious threat to our health!
Olivia, 13, Wales
Yeah. I've seen loads on the beaches in France. I never touched them but it's sad that they get washed up.
Elanor, 14, Loughborough
I see jellyfish all the time and my father can actually pick them up! It's amazing, though I wouldn't try it myself.
Melissa, 14, Tunisia
I never had a run in with a jellyfish, but I did see one before... what do I do if a get stung by one?
John, 14, Derry
Luckily I haven't but if I did I would scream!
Sophie, 13, Newbury
I've never been stung by a jellyfish, but I know several people who have. And once when we were on holiday my brother found a dead jellyfish in the sea. I thought "only one, and it's dead" so went in the sea. But then I saw that there were loads of dead jellyfish! I refused to go in the water afterwards!
Kate, 13, Aylesbury
Last year I went to Menorca and I saw about 50 big jellyfish! I kept my distance!
Charlotte, 12, York
No, but I almost picked one up, thinking it was a rock! That was in Ireland...
Hannah, 10, Bristol
In Spain me and my sis where swimming and she swam into one, if it wasn't for her mask she would of been blinded, she was ok though.
Mali, 12, Hurstpierpoin
My friend got rather worried when we were on holiday in Ireland and my family introduced her to the joys of jellyfish fights... the non stinging ones that wash up on the shore make excellent missiles to throw at each other! Although, yeah.. it is pretty disgusting.
Clare, 15, Stroud
When I was in Thailand I went snorkelling, and saw the BlueBoxar Jellyfish! It's really dangerous.
Tom, 13, Epsom
Me and my best mate were in Bournemouth on the beach in the evening for a walk... and we were running through the sea when I nearly ran into a HUGE dead giant jellyfish.. it was definitely dead but we screamed so loudly that the local volleyballers were giving us strange looks! Embarrassing when we look back at it now, but at the time it was such a shock!
Hannah, 14, Denham
Once when we were camping we found a big one stranded on the beach! It was HUGE, about the size of a chair seat! My mum and dad used some sticks to put it back in the water. It was actually quite pretty!
Katie, 12, Canada
On holiday we saw them in the sea and there were loads of people who would pick them up and throw them.
Rosemary, 11, London
I was stung by a lil' jellyfish in the sea. My arm went purple it hurt for a while but I got better!
Danni, 12, Sussex
I remember once when I was holiday when I was little and there was a dead jellyfish on the beach it was really really long!
Nicola, 15, Weybridge
We used to see dead ones on the beach in Wales. Some of the boys used to kick them about like footballs. It was disgusting!
Charlotte, 14, Liverpool