Skrenk

When the cloud of poisonous gas killed everyone on Liraj A'Talvo centuries ago, it also blanketed the magical laboratories of Kanan A'Talvo and left several experiments to run out of control. One of the more unfortunate results of this catastrophe was the skrenk.
The initial purpose of the skrenk is unknown. What is known is that it is one of the most dangerous creatures on Kanan A'Talvo.
Skrenks are fairly unremarkable-looking creatures of vaguely feline physiology. They are a flat, desaturated gray color with short fur similar to that of a laborador retriever, powerful jaws full of vicious fangs, razor-sharp claws, and a strong, semi-prehensile tail. They are about the size of a jaguar, and in terms of their predatory tactics, very similar. Skrenks fall upon their prey with teeth and claws, usually from ambush, and kill them through conventional violence.
Three things set a skrenk apart from other predators, however. The first is their ability to traverse almost any environment. Skrenks can survive underwater, traverse up sheer surfaces, and even slip into the astral plane briefly to get around obstacles. The second is their incredible intelligence. Skrenks are almost as smart as most humanoids, and work together with the environment and their amazing suite of traversal abilities to set up some truly diabolical ambushes for their prey. Third and finally, skrenks are entirely immune to magic beyond that of their own abilities. Spells simply do not affect them. Magical barriers present no obstacle either to their senses or their movement. Magical environmental hazards are completely ignored. The environment of Kanan A'Talvo therefore functions as something of a force multiplier. Skrenks can trap potential prey in magical hazards the skrenk can effortlessly traverse without risk and destroy them. They also can eat almost anything organic without difficulty, so virtually nothing is safe from their predation, save wholly synthetic beings like constructs.