Someone's instant messaging me! Wait, no they're not!

Earlier, I was chatting on Skype IMs.  

 When someone sends an IM, it goes, PWOOP! Well, I keep hearing multiple PWOOP!s like someone has messaged me, but there's nothing new added to the conversation!   What the heck?

Then, I realize that the extra PWOOP!s are coming after someone actually sends me a message. I look to the right...

 LO AND BEHOLD, Kai is mimicking the sound...and is calling back, PWOOP!, after someone IMs! Augh, it's so unbearably cute!!