Do you know the strain? Not that it would help with an explination, but I'm curious.
My first thought was that it's a Photoshopped pix, (different pistol maturity) but if it's not...
Perhaps a genetic anomaly, or something (bacteria, some sort of weird chemical interaction, hormonal glitch...) has interrupted that particular calyx's natural coloring abilities. Or, there's a now-extinct candy cane cannabud in it's distant genetic history.

Was this the only abnormal calyx? Was there anything else that was not quite right on the plant? Too bad it was a poor performer...would be interesting to see if you could encourage the trait by pollinating any and all calyxs' showing those expressions, and breeding those seeds together a couple of times, if the trait continues.

Likely it's dependant on it's 'greener' neighbors for it's energy, but I wonder if it produces trichomes differently than on normal calyx's? (stronger, tastier, smoother...)

Anyway...looks pretty cool. :thumbsup: