You can land it 70% of the time without ES by spamming doton.
Seriously though, there also seems to be something in its AI that it shifts to 'melee mode' from 'run away' mode if you do enough damage in a short enough period of time. If I nuke it as it runs by and it lands, it'll stop, kill me, and by then the others have done enough damage to where it just seems to hang out until it's pretty low, then runs off for a bit, then they finish it the next time it stops. Although I'm liking the ES-gravity idea better haha.