As far as Her Galloping Grace the IPU is concerned,
I quote from Hoofprints 4:14 (by the prophet Ixian):

Yea, and I was given by inspiration that She was
next to me, and I could touch Her, being the loyal
servant, and I laid my hand upon Her mane, and
She *was* Pink. She was not pink, She was not
colourless, but She *felt* Pink, and I was thus
overcome. I awoke later with a hangover, but I
knew She was *yet* Pink, but invisible.

Bryan Hayward