Defeat Brainiac was easy, you just had to use your powers to control the plants life, thus holding him in place and giving easy punches on him.

And well, you had the most conqueror of planets right on the floor, only for you. Of course that you used your plant pheromones to make him fall in a madly love for you. Now you have Brainiac on your feet and with his help you can finally end humanity and make the plants conquer the Earth.

"What do you want, my true love?" Brainiac says with his robotic voice and he get on his knees in front of you, holding your hand and giving a kiss on your backhand. "Ask me anything and I'll give it to you."