Immunity to kinetic energy is an advanced form of laziness. This is when you laziness is so ingrained into you that your body actually will NOT comply to your brain's commands to move, as your body is dissipating any potential energy thinking about becoming kinetic. Nearly everyone has experienced this for brief periods of time, often accompanied by the uttering of phrases such as, "Okay... On three..." and "Yup. Getting up now. Yessir."
There are also some individuals who are more prone to suffer bouts, and for longer intervals. The people in question are often referred to as lazy, which doesn't do them justice. They're not going to argue much about it, of course, due to their condition.
Some examples of types of people likely to have fits of immunity to kinetic energy fairly often are lazy roommates, supposed dead people, or Matt McDaniel, who may be either of the above. People with this condition are often difficult to deal with, as they tend to say "Okay" "Sure" and "In a minute" to nearly any request for them to do anything other than sitting on their ass, especially work so that they can pay rent. They do not, by the by, do these things. Not that I'm bitter.