Five new Slayer masks are available on the Squeal of Fortune from the 12th of July 2013, themed around five more Slayer monsters:
Mask of Mourning (banshees)
Mask of Gelatin (jellies)
Mask of Dust (dust devils)
Mask of Granite (gargoyles)
Mask of Vines (mutated jadinkos)
Equip a Slayer mask and you’ll find that its combat stats are geared towards fighting its related creature, damage is boosted (if you're on a related Slayer task), and extra Slayer XP is earned! You’ll also earn double drops for every tenth creature that you kill – there’s a handy counter that tells you how many you’ve taken out so far.
While wearing each mask, you can also ensure that - once a day - your next Slayer assignment is for its represented monster, and also teleport to locations where the creature can be found, twice a day. Each mask also acts as a facemask, and the banshee mask acts as a set of earmuffs.
After a specified number of kills, it'll no longer grant bonus XP, extra damage or double drops. It'll retain its other functions, though, and you'll unlock the ability to switch it to a new 'helm' form. Not only does the helm form look even cooler, it enables an awesome creature-specific emote.
Any questions on how the slayer masks work? For full details of each of the ten Slayer masks, head on over to the wiki.
You’ll have your best chance of winning both the new and old masks from Friday 12th July 00:00 GMT until Sunday 21st July 23:59 GMT. After this, the masks will remain on the Squeal of Fortune, but you'll see them less frequently.
If that’s not enough, maximise your Slayer XP earnings with Slayer pendants and recharge gems up for grabs on the Squeal of Fortune, rs gold also until the 21st of July.
Everyone gets at least one spin on the Squeal of Fortune per day, and can earn more through gameplay.