Yesterday, some race thought they would attack my planets. So I killed every one of their colonies, then royally forgeted their home world. Home worlds, at the moment for me, are really hard to take. So what I did was buy two meteor showers and 5 drought generators and just killed all the life on it.

Basically it dropped the T score from 3 to 0 within like 10 seconds turning the planet into a super heated wasteland. Since the T score was so low, all their cities were destroyed and a single bubble colony was left, which was easy to remove.