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The Masque dragon has been added with a specific breeding combination.
Moonstruck + Spritely
This combination of dragons has the elements plant, fire, earth, cold, lightning & air. An awful lot of dragons can result from those 6 elements.
53 dragons with a set breeding chance, for a total of 205.5%. The 1.5% is more than halved to 0.73%, which means 127 attempts for an even money chance to get one. 16.77 hours average fail time, means you need to breed 88.74 days for a 50/50 shot of breeding one. The 13 attempts you get in the 9 days left in this event gives you 9% chance of breeding one.
Clone a Masque Dragon
Masque shares the same elements as the breeding pair, but has a 4% chance of cloning. I recommend
Poison + Masque
We skip the chance of cloning Moonstruck and Spritely, so only 78 dragons (lol) and the extra cloning percentage for the Poison dragon takes total set percentages to 211%. 4% cloning chance drops to 1.9%, which means 37 attempts needed for a 50/50 shot of getting one. 15.41 average fail time means 23.76 days of non stop breeding for an even money chance of getting one. 15 attempts possible in the 9 days left, which gives you a 25% chance of getting one.
May the odds be ever in your favour.