About five years ago someone graciously sent me a lump of Java moss. Maybe a small handfull, if that.
For a while I let it grow unchecked in my betta rearing tank. Then in several tanks. Then I started pawning it off on anyone that would take it. I thought, at one time, it was -gone-... no... no it wasn't.
Now, about a year later I have a five gallon betta tank being taken over by the stuff. It's growing on the driftwood, it's growing on -other plants-... I think it may also be growing on the betta.
I point at it, I shout for it to stop growing. I make disparaging remarks about it's mother, and it's relationships with livestock. It keeps growing. I've considered pulling out a clump and roughing it up a little as a lesson to the others.
Maybe I can find a way to trade it off for CP's some day.