Hypnotoxin a neurotoxin found in the tentacles of the Portuguese man-of-war that depresses activity of the central nervous system.Nematocyst. Nematocyst, minute, elongated, or spherical capsule produced exclusively by members of the phylum Cnidaria (e.g., jellyfish, corals, sea anemones). Several such capsules occur on the body surface. The threads of some nematocysts ensnare small prey by wrapping about them.

Nematocyst paralyzes the prey by injecting Hypnotoxin.

Nematocysts are specialized stinging cells found in organisms such as jellyfish, sea anemones, and hydra. These cells are used for defense and capturing prey. Nematocysts contain a coiled, thread-like structure called a cnidocyst, which is filled with venomous toxins.

Function of Nematocyst:
The primary function of nematocysts is to paralyze or immobilize the prey. When the organism comes into contact with its prey, the nematocyst discharges rapidly, injecting the toxin into the prey's body. This injection helps in immobilizing the prey, making it easier for the organism to capture and consume it.

Hypnotoxin:
Hypnotoxin is the specific toxin that is injected by nematocysts. It is a neurotoxin that affects the nervous system of the prey. The toxin disrupts the normal functioning of the prey's nerve cells, leading to paralysis. This paralysis prevents the prey from escaping, allowing the organism to capture and consume it.

Other Toxins:
While hypnotoxin is the main toxin injected by nematocysts, other toxins may also be present. These additional toxins can vary depending on the species and can have different effects on the prey. For example, some nematocysts may inject cytotoxins that cause cell damage, while others may inject enzymes that break down tissues.

Conclusion:
In conclusion, nematocysts paralyze their prey by injecting hypnotoxin. This neurotoxin affects the nervous system of the prey, leading to paralysis and making it easier for the organism to capture and consume its prey. It is important to note that different species of organisms may have different toxins and mechanisms of prey immobilization, but hypnotoxin is a common toxin found in nematocysts.