Why jelly fish are poisonous?

3D illustration background of jellyfish. Jellyfish swims in the ocean sea, light passes through the water, creating the effect of volume-rays. Dangerous blue jellyfish

JELLYFISH is a beautiful free swimming marine animal. They are bestowed with umbrella shaped bells and trailing tentacles, although a few are not mobile, being anchored to the seabed by stalks. The bell can pulsate to provide propulsion and highly efficient locomotion. Due to climate change, jellyfish are found everywhere. They have no brain,