More children's TV level of astrophysics: so you keep adding energy to your particles, they approach 1c, they gain and gain mass... until they collapse into nan

More children's TV level of astrophysics: so you keep adding energy to your particles, they approach 1c, they gain and gain mass... until they collapse into nanoscopic black holes and immediately evaporate into hawkins radiation, right? I mean that's the general upper limit on stuff in the universe: it eventually collapses into a black hole.