One that PolitiFact called "pants on fire." They checked the sources listed in the ad and made a couple of phone calls, and the whole house of cards starts to crumble.
Well, that's not enough. After all, it takes some effort to get the message out that this well-funded "independent" group is lying.
So, you create your own video. And you encourage your supporters to share it with their friends:
Best line of the rebuttal?
"I keep hearing about Tumbler and whatever that is, use it too."