Pokeball

The Pokeball is a specially made device used for catching Pokemon. You can capture a pokemon if you attack it and has a red life bar. Also, the wild shiny Pokemon have a red life bar all the time.

There are different types of pokeballs, like the Master Ball for example. But as of now, the normal Pokeball is the only usable pokeball in PTD, but a Master Ball does make an appearance in the Cerulean Gym 2 cutscene.

Ash loses his Master Ball in the Cerulean Gym cutscence when The General comes and uses Psychic on it.