adverb, adverb taking the 'to' particle
rustling sound; rummaging sound
Mimetic adverb describing a soft, dry rustling or rummaging noise, often used with と to modify a verb.
引き出しの中でごそりと何かが動いた。
Something rustled in the drawer.
彼はポケットをごそりと探った。
He rummaged in his pocket with a rustling sound.