Yes
If you stuck your finger into a prickly pear cactus, you could get stuck with one of the spines. You could also possibly be bitten by a spider who likes to make their webs in the prickly pear.
The cactus adapted to its harsh environment by developing thick skin to slow the evaporation of water. The leaves changed in order to reduce the surface area that water could evaporate from and over time became defensive spines to protect itself from animals trying to get inside its thick skin for the moisture. The cactus makes its food, by having chlorophyll throughout the rest of plant. That is why the entire cactus is green.
A cactus (there are many species) is likely to be covered with very sharp spines. Apart from painfully drawing blood, any dust and bacteria on the spine that punctured your skin could cause a wound or blood infection. Some cacti have spines so close together that it is possible, with care, to pick up the plant with bare hands (similar to someone laying on a bed of nails without harm). Other cacti have spines so long that it is too difficult to handle the plant without very thick leather gauntlets.
A weed is a plant growing where it is not wanted. A cactus growing where it is not wanted could be considered a weed. Prickly pear cacti frequently are labeled as weeds when they take over pasture land.
saguaro cactus
The cactus adapted to its harsh environment by developing thick skin to slow the evaporation of water. The leaves changed in order to reduce the surface area that water could evaporate from and over time became defensive spines to protect itself from animals trying to get inside its thick skin for the moisture.
It looks like you are asking about the saguaro cactus. There is no type of cactus with a name that is any closer to "saroya".
Cactus plants hold water temporarily in their roots. They also hold it temporarily on their modified leaves. They hold it permanently in their stems.
to protect itself from creatures that could harm it.
The water from the cactus could be cleaner.
It could, but it would get some of its tentacles cut by the lionfish's sharp spines.
Wherever it grows, the cactus functions as a conversation piece because of its unusual appearance, its drought tolerance, and its adaptability to indoor and outdoor environments.