In this video guide I will show you how to defeat and enemy by colliding them with another enemy. There are several different ways and spots to do this. I will show you a few easy ones along the story path so you don't need to go looking for one. This is also after I got the Force Push ability. Using the
Force Push will be the easiest way to obtain the achievement.
The first spot I noticed was when doing the objective Explore the Tomb of Miktrull. This is also on the planet
Zeffo. Before getting to the tomb you will notice some plants on the ground. If you get close to them they will swell and explode. When you reach these plants you should see a rat behind it. Just Force Push one of the plants at it and it will home in on the rat. Killing it in one hit will give you the achievement. Now if you miss, the plant will re-spawn. Then you can have a shot at Force Pushing the one plant into the other for the achievement.
Another good spot if the spot earlier didn't work, is right after the previous spot. This spot is just a little after the first one down the path. You should see an open room with platforms to jump on to progress. You should also see some more plants and a rat. Just get behind the plant to line it up with the rat and Force Push it into the rat, will pop the achievement.