This was a while ago: In an episode of Are You Afraid of the Dark? two siblings are sent to a fancy private school where music is banned and the students are fed some mystery gruel at lunch, which the siblings only pretend to eat. Late at night, every night, the students, affected by the mystery gruel, sleepwalk to the school basement where they feed something to a large number of eggs floating in a pool of water.
Turns out the faculty are members of a race of lizard people posing as humans who use the students to nourish their offspring and eventually intend to feed the students to the new generation once the eggs hatch. However, one of the siblings uses the high frequency sounds from the music on his Walkman to kill the lizard people's queen/mother, the faculty and the eggs—though if I recall correctly, at least one egg remains intact and it's implied the lizard race might survive.