This actually happened months ago, but I forgot to post about it until now.
We attended a playgroup birthday party. I don't know if you've ever been to a party with 8-10 toddlers present, but it's chaos. Not even controlled chaos. You were lucky if you didn't have a truck rammed into your ankles. At the party the following happened:
Alyssa, the birthday girl, had a toy which the kids could sit on and spin (called, amazingly enough, a Sit 'n Spin), but it wasn't obvious to them how to work it. Isaac was trying to use it but failing, so his mother grabbed a life size (to a toddler) Elmo doll to demonstrate how it worked. As an aside, Elmo is a beloved character for almost all the kids. Well, Isaac got mad because Elmo was using his toy, so he tackled Elmo and started choking him. Seriously. This caused Lily to start wailing because Isaac was attacking Elmo.
I'm sure it was traumatic for Lily, but to the adults watching it was quite funny.