Lightning is often considered a form of plasma, which is a state of matter distinct from solids, liquids, and gases. Plasma is created when gas becomes ionized, meaning that the atoms lose some or all of their electrons and thus acquire electrical charge.
During a lightning strike, the temperature can reach up to 30,000 Kelvin (around 53,540 degrees Fahrenheit). This extreme heat causes the air surrounding the lightning bolt to ionize, leading to the luminous and conducting state we recognize as lightning.
Additionally, plasma is found in many places in the universe, not just in lightning. For example, stars are primarily composed of plasma. This makes lightning an interesting and accessible example of plasma that we can observe here on Earth.