Plants vs. Zombies Garden Warfare 2

THE YELLOW KING! King of the wimps! King of the giver-uppers! King of the cowards! King of the not-courageous! This guy's round 15. To get to him alive and with good health remember to focus power units to keep your damage minimal. If you're struggling go on a minion cull to bring back some health. Don't collect all the infinity shards you see; they will sit there until the king is dead. Use them as health sources and leave them lying around if you're good for damage control.
YOU MADE IT TO THE KING? HERE'S SOME TIPS!
EDIT: The king is located in the Infinity Time game mode. This unlocks for you after you finish either the plant campaign or the zombie campaign. The first time you do it is free; from then on you have to pay stars to get in.
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FOCUS THE KING! After you do enough damage our yellow friend will summon in reinforcements AND DISAPPEAR. Mini bosses will spawn to fight you. This is where it gets a little interesting.
Your tactics should be taking out as many of the little guys as you can first. Once the mini bosses die the king will spawn back in and more enemies will come and holy moly you could get overwhelmed quick if you're not careful.
Make sure to use all your buttons on the mini bosses to take them out quick without taking too much damage. If you can, try to save the for when the king spawns again. After he comes back, FOCUS THE KING AGAIN! once he's down the round will end and you move on like a champion. If you have a lot of health ignore precautions and just pump in that power move damage. As you've learned from reaching this point, your health is maxed after you defeat a king and move on to the next place.

As for fighting tactics for the king himself:
- When you get too close to the king, he shoots out a constant beam of energy not unlike that shot from your dino (if you're doing this as a plant) that eats your health away pretty good. Try to keep your distance from him at all times.
- When you're far away he shoots slow high damage balls of energy at you. SERPENTINE! Stay outta the way of those suckas! Worst case scenario you can just hide behind a rock until the king cools down and stops pumping at you so you can get back in the fray.
- USE THAT POWER! HEADSHOTS DO MORE DAMAGE! I found if you aim slightly above his head you get more criticals.