I actually saw one recently that had a panda walking through, but just to still get everyone who knew what to look for, they altered other properties of the sce

I actually saw one recently that had a panda walking through, but just to still get everyone who knew what to look for, they altered other properties of the scene and after the panda reveal, then reveal the multiple other, now obvious changes that were made. I won't specify in case someone hasn't seen but it was pretty amazing.