Someone slotted me head126-blink.gif
It let me keep it, but when you change heads the blink effect is gone? It's not a shield, it's very strange. The person who originally slotted me said it was rare from the randomhead command. When you tap heads it is on page 8, the page with the same head but you can only normally equip the non blinking gif. I tried selling it in the upload house but as expected, it's not an upload. Quite strange you can't normally equip it from the heads menu. I have also seen a blinking variant (worn by the same person who slotted me the one I now have) of the blonde head on page 26.

Add me on classic, my username is ZedFox and I can slot you to experiment with it. I recommend saving the slot as once you equip a different head, you can't switch back.

 

I have a few blinking heads that I bought at Snow Town before that are defaults but they're blinking.  

I guess then what's happening is that you are able to slot other players the heads even if they don't have them. My guess is that the filename is almost identical, the difference being the "-blink" at the end of the file, so the game thinks they are in fact the same file, and temporarily replaces them.  

everyone have the img file that's why you can wear it lol i have the .gif file if you want it.

also took a look more into and seems like there are more blinking default heads lol