How can I make NPCs "pass through" players?

I'm doing some work with AI and have been having quite a few problems. If I could get the result seen in the video linked below, however, it would solve a few of them. How can I make NPCs pass through players like shown here?

Video

Is the creator setting a CanCollide property to false for a second, forcing the player upward? I'm not really asking for code, just an explanation as to what properties they're changing so that I can attempt to replicate it. Thanks in advance.

for i,v in pairs(game.Workspace:GetChildren()) do
	if v.Name == "NPC" then
		for a,b in pairs(v:GetChildren()) do
			 b.Touched:connect(function(hit)
				if b.hit then
					b.CanCollide = false
				end
			end)
		end
	end
end

I dont know if this will work but I gave it my best shot.