Excellent preset for Datamoshing - Avidemux 2.5

Touch nothing else on MPEG-4 ASP (Xvid) encoder preset.

Frame:
Interlaced: <any, except off>
Maximum I-frame Interval: 5

B-Frames:
Maximum Consecutive B-frames: 2

Quantiser:
Quantisation Matrix: MPEG Matrix

Set the audio to AC3 audio, because if you don't the audio will appear to go faster on Windows Media Player and will stutter on VLC.

Then use AviGlitch tool using Ruby (install Git, it comes with Bash and MINGW, which can natively run Ruby and Bash) :
$ sudo gem install aviglitch

then

datamosh (file).avi


WARNING: This does not support 720p60 or 1080p60 video. Make sure you downmix the video to 30fps before attempting this.
WARNING: DO NOT USE NEWER VERSION. They don't work that way. Only use 2.5.x version.
Tip: The more colorful the video is, the more mushed the video will look. My experiment with music videos and JaboodyDubs' video, as well as a footage from IMCF event ended up with extremely mashed video.