The "Top Network Askers" sidebar shows a bunch of similar gravatars for users, where their gravatars are actually something different. In this case they all seem to link to
<img src="https://www.gravatar.com/avatar/?s=18&d=identicon&r=PG&s=30"/>
Clicking through to the users shows different gravatars (since you can't click on the image, here are a few):
- https://aviation.stackexchange.com/users/27070/florian
- https://travel.stackexchange.com/users/94549/sally-nguyen
- https://parenting.stackexchange.com/users/35433/rachel-bailey
