Parasite beetle

A species of beetle that is highly magical. They spend the first part of their life eating and storing up magical energy in a concentrated form in their bodies. Upon accumulating a sufficient amount of energy they will take flight seeking out a larger creature, particularly mammalian creatures with softer skin.
  They have hooks on all of their 6 legs, on their back end and even their pincers are hooked. This is all so they can fly onto the back of a creature around the upper back at the spine and anchor themselves in place while they initiate the incubation process.
  After anchoring they release their magical energy, paralysing the host and growing a thick cocoon around them. During the incubation they grow chitinous armour across the bodies of the host and creating links to the creatures spine and brain. Once incubation is complete the creature is completely covered with twisting organic chitinous armour fused directly into their flesh. The head having large semi-transparent windows located at the creature's eyes and an insect like maw with pincers and a retractable proboscis located at the mouth. The head is also adorned with a chitin horn similar to a stag beetle but varying in shape, this horn is a focal point for the beetle's magical capabilities which often amount to creating searing beams from the horn. At this stage the beetle will usually have completely integrated with the brain of the creature, using the creature's brain as it's own but having it's insect will be in control.
  Recovered host specimens when the armour is removed appear pale, not having sunlight touch their skin. Their skin having holes and markings where the parasitic armour was affixed. Their bodies can also be unnaturally stretched or squashed to fit the form the beetle desired the body to take. Limbs can be long and gangly, digits fused together, spines crumpled and ribs pulled in wrong ways.
  Magically inclined organisms are often able to resist the beetles, preventing them from anchoring and resisting the effects of the magical paralysis.
  Sapient creatures are also sometimes targeted as hosts, usually humans being the most commonly taken due to the lower levels of magical ability in the general population. There are some edge cases where humans where able to retain some level of their mental faculties due to the higher complexity of the sapient brain being more of a challenge for the beetle to dominate. Those that do however often wish that they hadn't, their bodies now covered in chitin, unable to feel the warmth of the sun on their skin nor the cool breeze across their face. Their real bodies encased and their minds linked to that of a creature who's only intentions are feeding and reproducing.
  In these cases the insect's influences manifest as a voice inside the host's head, piggybacking off the language centre of the brain to communicate. The insects are able to access much of the data stored in the brain too including memories and the host's emotional state. Both parties have partial control of the body, the insect able to directly input signals into the spinal chord but lacking the fine motor skills contained within the host's brain. Although a horrific existence the new form will have much greater strength, agility and durability than the original host.
  Beetles who take a sapient host are able to access the higher intelligence and use it as their own, understanding language and complex concepts.
  They are able to go into cocoon states again at will, repairing extensive damage to the armour or changing it up to try and optimise their form. It's also possible for more experienced beetles to create wings.
  Reproduction is done by a male and female beetle finding each other and preforming a joined cocoon. Temporarily separating from the hosts, leaving them in a paralysed state during the encounter. The female will then lay the eggs in another cocoon, sometimes forming chitin armour around it for protection.