For anyone wondering about the different taming games for the three heads.

Poison: Feed the head as it bites to fill its bar, extraordinary kibble works best

Fire: It will mark different creatures near you, kill enough of them to fill the bar

Lightning?: The middle one requires you to play a game where you control a bar and have to keep it on the arrow displayed on the taming bar, this arrow will move rapidly, as per the others do this until you fill the bar.

Finally you just knock it out a 4th and final time. (You have to knock it out 3 times prior when you are initiating the minigames)