Today, researchers at the California Institute of Technology revealed that they've created see-through mice. These creepy little guys will be used to help scientists track how disease makes its way through the body.

The Associated Press describes the process by which the mice become transparent:

The see-through technique involves pumping a series of chemicals through blood vessels, as well as other passages in the brain and spinal cord. Some chemicals form a mesh to hold tissue in place. Others wash out the fats that make tissue block light. It takes about a week to create a transparent mouse.

Before all that, scientists euthanize and skin the mice. According to the AP, researchers can make rats transparent as well.

[Image via AP]