In the original Subnautica game, you can find Kharaa infected creatures. Some of these such creatures, such as Peepers, can be picked up and put in an aquarium. If uninfected fauna are put in the same aquarium, they will soon become infected as well! What's especially cool, is that if you find a Peeper with enzyme 42 and put it in an aquarium with the infected creatures, their green pustules will begin to dim! Just though this was a pretty cut little detail.