Left mouth radical — the indexing radical, a pictograph of the open mouth. Files
嘭 in the family of sound-emission characters:
啪 slap-sound,
哗 splash,
嗡 buzz,
砰 (also 'bang' with stone radical). Marks
嘭 as an onomatopoeia — the booming or thudding sound a heavy object makes when it strikes.