They can be. In 2010, at a New Hampshire beach, pieces of a single dead lion's mane jellyfish stung between 125 and 150 people.
A dead jellyfish decomposes.
Yes
First of all, the man-of-war is not a true jellyfish. Its body is filled with air. To be a jellyfish the "bag" of their body has to be filled with water. Also a box jellyfish is more dangerous. The box jellyfish is the most dangerous jellyfish in the world.
The box jellyfish is lethally dangerous if you have been stung over more than a few square centimeters of skin.
yeswithout the cell the jellyfish is dead
Their venom.
Clear
Most jellyfish are not dangerous. The Man o' War has the ability to do some painful damage to your skin, but it is not a true jellyfish . . .
Yes, both dangerous and friendly :-)
They can sting you and it hurts! Trust me, I know...
Some jellyfish stings are dangerous to humans.
A jellyfish has tentacles which can sting by injecting a toxin. Jellyfish can be extremely dangerous, despite being a very primitive type of organism with no skeletal system.