Totally Accurate Battle Simulator

This achievement can be obtained multiple ways.

Go to sandbox.

You will need at least 8 or 10 Cheerleaders together with either Blackbeard, Da Vinci Tank or Lady Red Jade. This works by just placing them in the same team and launching the battle, a tornado will form after a short while and the achievement should unlock.

Keep in mind that all except the Da Vinci Tank are from the "secret" category and you will need to find them around various maps by looking at a certain item that usually resembles them.

Cheerleader can be found on Tribal 1 (on the highest elevated cliff that you see when you look forward from where you spawn, it's behind some rocks on top of a white log.)
Blackbeard can be found on Pirate (go through the cascade on the left of the mountain)
Lady Red Jade can be found on Dynasty (on top of the first roof layer in the front middle) This one is a bit tricky since apparently you can't see the item for some reason.

Edit: The Mace Spinner works too.

Leave me some feedback since this was my first guide.

Use Mace spinner and cheerleader