Answer: kerplunk

AnswerCrossword Clue
KERPLUNKWith a thud
KERPLUNKPlopping sound
KERPLUNKWith a thud.
KERPLUNKDropping sound
KERPLUNK... a raindrop in a puddle
KERPLUNKPlop's kin
kerplunkto drop with a heavy sound