mucus – n. a thick liquid that is produced in some parts of the body
slimy – adj. thick and slippery
secretion – n. the production of a liquid by part of a plant or animal
disrupt – v. to cause something to be unable to continue in the normal way
intruder – n. something that is not welcome or wanted in a place
petri dish – n. a small, shallow dish that has a loose cover and that is used in scientific experiments especially for growing bacteria