flea in one's ear
A stinging rebuke or rebuff.
If he bothers me again, I'll send him home with a flea in his ear.
ADJ
cat, dog, etc.
VERB + FLEA
get, have | be riddled with
control
My cat scratched constantly until we finally controlled the fleas with a new treatment.
FLEA + VERB
jump | bite | carry/spread disease
FLEA + NOUN
bite | collar, powder