Well I do know there is a parasite that gets on a ant and it turns it into a sort of zombie.
And there is a grub, that actually leaves poo that ants are attracted to and they eat it thus they pick up that parasite. That parasite then goes through the ant's body, the ant stays at the end of a grass blade or whatever, and the slug comes up and eats the ant. Then it goes back around again.
I did not watch the video. I am merely remembering (and paraphrasing) information I once remembered hearing about ants.
I find ants, insects in general, fascinating. Mainly because ants are very militaristic!