Ah, yes, Planet Busters. PBs cause big problems. I once tried to control a massive Fungus Bloom, 3 pops in one area, in a single turn, with a planet buster. I was also building the Voice of Planet secret project at the time which triggers Fungus Blooms every turn until its completion. The PB caused my planet pollution score to really shoot up and I was soon buried in Locusts. I lost the all the bases on my main continent and other factions on nearby continents lost bases as well.