Another spooky tale from the haunted bathroom

Remember the mysterious o-ring? The o-ring that appeared out of nowhere in my shower?

Well.

Yesterday morning, I was showering away, when I looked down and saw ... blue. Splotches of blue, like blue paint, on the floor of tub. Splotches that had not been there when I got in the shower.

Bright blue. I actually looked up, to see if bright blue paint was somehow leaking through the ceiling above the tub.

Nope.

I touched one of the splotches with my toe, and it smeared, just the way paint would.

I'm estimating there were thirty splotches, bright blue splotches, ranging in size from the eraser on the end of a pencil to dime-sized. They just appeared, while I was showering. I always, always do a quick scan of the tub and the tub surround before I get in, because spiders love my bathroom, and there were no blue splotches before I got in the tub.

I do not use any type of product in the shower that is blue. No blue shampoo, no blue body wash, no blue nothing.

I used my buffy-puff-body-wash-sponge thing to scrub at the splotches. They smeared and faded, but they're still there, faintly.

Ideas? Back when the mysterious o-ring appeared, I thought it was funny. And I think I finally figured that out - the o-ring had a hairline crack that allowed it to fall off the showerhead. But bright blue splotches? Out of nowhere? Appearing on a tub floor while I am showering?

Okay, this is kind of weird.