Celebrate the heroic puff monster by having a level 10 puff. Make sure it out from Hall of Champions.
Reward: 500 xp and 200 food.
 Celebrate the heroic breeders! Harvest mount melons (small farm) or lucky lettuce (large farm).
Reward: 600 xp and 1000 coins.
 Breed a magma monster with an earthquake and then hatch an egg. Fact: you only need to have earthquake and magma monsters (both are level 10) and then hatch random egg (fire??). (Thanks to Brian for this info)
Reward: 200 xp and 150 food.
 Celebrate the Memorial Monster: have a level 10 memorial.
Reward: 250 xp 10diamonds
 Celebrate the Marine Monster: have a level 10 marine.
Reward: 800 xp and 10 diamonds.
Hatch a memorial monster in honor of Memorial Day.
Reward: 250 XP and5 Diamonds
Hatch a marine monster in honour of Memorial Day.
For veteran players (who have got the monster before), if you don’t get this monster it’s probably because your memorial is outside, to get the quest simply move your memorial to hall of champions. Close the game (not minimize but “real” close where you can see the loading screen again when you start the game). The quest should be available now, if not then I don’t know what to do :D.
Reward: 250 xp and 5 diamonds