Possible Clues:

• Sound of a dropped tomato
• Pie-in-the-face noise
• Tomato-hitting-the-floor sound
• Sound of a pancake hitting the floor
• Sound of a dropped scoop of ice cream
• Gelatinous thud
• Fittingly titled paintball magazine
• Part of chair back left in row
• Sounds like wet cloth hitting floor with petty quarrel over letterhead
• Comical sound of hitting the ground