I tried using the search feature on this forum but didn't see anything about this...that, and I've looked all over Twitter and Google and didn't find much of anything else. Feel free to ignore if this was asked before --- this is the first time I've ever played MyTeam.
I was rotating a Bruno Caboclo card I acquired in a pack when the bronze stripe on the side started "glitching" out. I thought it was a graphical glitch but it stopped after a few seconds, after which a "rune" symbol attached itself to the bronze stripe:
I tried this for other cards in my collection but nothing happened. Does anyone know what this feature does?