Antiprotons are subatomic particles that are the antimatter counterparts of protons. While protons carry a positive electric charge, antiprotons have a negative charge. They are produced in high-energy environments, such as during cosmic ray interactions or in particle accelerators like the Large Hadron Collider. When an antiproton encounters a proton, they can annihilate each other, resulting in the release of energy in the form of gamma rays. This annihilation process is a key area of study in particle physics, helping scientists understand the fundamental forces and particles that make up the universe.