This is the 11881st most frequent Polish word.
krzakach
"In the bushes."
The term 'krzakach' is in locative case, describing the location where the dog was running.
Pies biegał w krzakach.
The dog was running in the bushes.
The word 'krzakach' in the locative case indicates the place where the keys were lost.
Zgubiłem klucze w krzakach.
I lost my keys in the bushes.
In this sentence, 'krzakach' locatively specifies where the strange object was found.