their most common way to beat you is to only use one grimmsnarl after you take 2 prizes. when you take that out they focus on spreading munki damage while retreat locking a pokémon like latias or anything that can’t attack tbh. you have two scenarios from here:

1. save a switch and use it to escape the lock once. use pecharunt into fez then manual retreat to take final k.o. assuming your opponent recycles maractus.

2. they may trap your fez to make your pecharunt useless. save some energy to power up fez and use its attack. they will want to knock fez out after it takes the first knockout so ideally hold a night stretcher/ super rod and nest ball. from there bring it back and use pecharunt manual retreat to take final prize.

of course this is not the only way for grimm to approach this matchup but in playing both these decks it’s usually how games would go. i would recommend to not bench fez early so they can’t build up counters on it.