The next mutation type under the 'Spread Class' type infected were what the ingested memories referred to as the 'Plant Infected'.
It was a very special type of infection, which -unlike the normal spreading of the diseases were the extremely rare cases when it came in contact with floral lifeforms.
This also made Aziel ponder about the possibilities that the origin of this so called 'O-620' was most likely not from this world. Question was where did it came from them? And for what purpose was it sent here?
In any case, it was a possibility once the virus has come into contact with plant life and thus a drastic change would occur. Smaller plant life will grow small needles across its mass that can be fired at any uninfected targets, causing mild discomfort whilst discreetly converting them.