User blog comment:Ghostly Owns/Secret Base Early Game Boosting Trick/@comment-26945286-20200709080450

If you have a bunch of money to spare, you can also make use of the secret base trainer. As far as I can tell, the lvl90 Audinos have nothing they can do to hit a ghost (or get rid of a burn, when I used a yamask), so I went in with my lvl9 freshly caught haunter(hold leftovers) and the pokemon I was leveling and killed them all no problem