Eric: "Dave! Good to see you, what took you so long?"
Dave: (in front of date he brought) "had to take an MMD but it's all good, I'm here now."
MikuMikuDance (MMD) is a free Japanese 3D animation program, used to make mostly videos staring (mostly) characters from another Japanese software, Vocaloid. Though characters from other things are used too. Because it is free, many fans make fanmade videos with it or even little skits.
Person 1: Woah, what program did you use to make this video? Claymation?
MMD user: No, I used a freeware program called MMD. It's really easy to use, and is 3D!