Never seen anything like it! (REALLY REALLY wish you and Jennifer&Stevens would collect the larvae you find, because the 3 of you find really odd ones.) If y'all would be willing to collect them (with as much info on the plants (nearby) and then contact me, I'd be more than willing to come get them and try to rear them.)
In this case, are the green bits algae? Is the purplish red color paint, or some sort of plant growth over rock?