Celtic Heroes

I just logged on my alt, killed a few connacht and got this
Never seen before after 8months Of playing

they were very common at halloween event, now they are a rare spawn

Which mask is this?

POST THE STATS 0:

it adds like 2@ to dex and st i think

they are green or white color.. i think..I have the white ones and they add +15 foc and +15 vit.

What are odds of getting one nowadays

Completely random, I'm taking a wild guess saying 1/350

Been playin a year now and have never seen one.

These mobs are from Samhain 2012, there were semi-rare mobs in lirs, shale, stonevale and otherworlds (about as rare as the torch bearers, maybe a tad more common). When killed, they would drop a batmask, which adds to a certain stat. If I recall correctly, there were 6 different levels of masks, the higher lvl mobs would drop higher lvl masks. They went from +5 to a stat to +20 (or +25, can't remember offhand). After the event they became very rare mobs, I have only seen them twice since the end of the event, both in that exact same spot. Although I have heard people say they have seen the others once or twice.