Try some of these & see if they help. You'll probably find that you do something better if you just muck around with a few of these.
Think there's some liquid morphing:
https://community.adobe.com/t5/after-effects/liquid-logo-animation-in-after-effects/m-p/11964960#M168130
Take a look at CC blobylise - a few vids on youtube. Don't think they are using this on the animation you've posted, but you could probably get some similarish effects out of it.
Also my guess is you'd want to look at this as well.
https://www.google.com/search?q=animate+line+along+path&rlz=1C5CHFA_enGB889GB889&oq=animate+line+along+path++&aqs=chrome..69i57j0j0i22i30j0i390.6280j0j7&sourceid=chrome&ie=UTF-8#kpvalbx=_6Sd2YOTuMc6M9u8P8Ou10AM18
Try mixing in the above suggestion with on of AE's particle effects (particle world etc).
You'd probably also get some cool results adding some turbulent displace on.
Finally, bet you £1m whoever has done this has used a plugin of some sort. It's not a very current animation & lot's of people were doing these 2/3 years ago. hence bet it's been Envato'd / sold as a plugin.