Answer: spitballs

AnswerCrossword Clue
SPITBALLSClassroom missiles
SPITBALLSIllegal pitches
SPITBALLSClassroom projectiles, perhaps
SPITBALLSHard-to-hit pitches
spitballsAn illegal pitch made with a ball moistened with saliva or another substance to make it move erratically
spitballsA piece of paper that has been chewed and shaped into a ball for use as a missile
spitballsSPITBALL