Microbiologists in South Korea report this week in mBio that the bacterium Chromobacterium piscinae produces cyanide when under attack from Bdellovibrio bacteriovorus HD100, a microbial predator found in rivers and soils that ingests its prey from the inside out. The researchers found that the prey produced levels of cyanide high enough to inhibit, but not kill, the B. bacteriovorus HD100.