While in his bat mode Megatron was able to emit what he described as his "sonic pain wave" from his wings; like most RiD abilities, it is voice activated. It takes the form of blue beams emitted from his bat wings, and it causes pain in organic lifeforms. Whether it causes pain in Transformers is unknown.
When Megatron arrived on earth in search of energy, he kidnapped Doctor Onishi. When the doctor refused, Megatron transformed to bat mode and used his sonic pain wave, causing pain in the humans. The Sonic Pain Wave was never used again.