It seems you might be asking about vesicular parasites. "Vesicles" are small, fluid-filled sacs found within cells, and "parasites" are organisms that live in or on another organism (the host) and benefit from it, often at the host's expense.

Here's what you need to know:

There's no specific parasite called a "vesicular parasite". The term itself doesn't describe a particular organism.

However, many parasites use vesicles as part of their lifecycle:

* Intracellular parasites: These parasites live inside host cells. They often manipulate cellular processes to form vesicles where they can replicate and hide from the host's immune system. Examples include:

* Viruses: Many viruses use vesicles for transport within the cell or to bud out and infect new cells.

* Protozoa: Certain protozoans like *Toxoplasma gondii* live within vesicles called parasitophorous vacuoles.

* Bacteria: Some bacteria, like *Chlamydia trachomatis*, reside within vesicles called inclusions.

* Extracellular parasites: These parasites live outside host cells but may use vesicles indirectly. For example, some parasites release toxins or enzymes packaged in vesicles to damage host tissues.

To better understand what you're asking about, please provide more context:

* What specific organism are you interested in?

* What aspect of its lifecycle or behavior are you curious about?

With more information, I can give you a more precise and helpful answer.