In Halloween town you see everything normal..like what you would see every year...But this year theres somthing not quite right...All the town folks can't seem to figure out whats different.Have a walk around to see if you can spot anything 
Quest begins when you visit everywhere in halloween town... Shops,Houses,Buildings and monsters maps..everywhere etc (If possible,if not just stick to in a house? the mayor of halloween town)
Ok so it begins
You walk around everywhere in halloween town...like every year/you walk into the mayors house
*Quest log shows up*
Somethings not quite right this year...can you spot it?
Maybe you should talk to people in halloween town.
Npc 1:
I think hallowen town is fine this year.
Npc 2:
Something's up nobody has come trick or treating this year.
Npc 3:
I don't know if this is suppose to happen or not..but this year theres no pumpkins (oh no D:)
*quest log*
Maybe you should check out the pumpkin patch east of cross roads.
When you go to the pumpkin patch you see its all gone...all the pumkins have been stolen.You go investigate...You see a trail of pumpkins. When you follow the pumpkins into a cave. There are walking npc's with pumpkin masks...(the walking npc's will be on a safe screen and the cave will be blocked so you can only see the npc's but not go in and kill them)
You go back and report it to the mayor/npc...anyone and he says "Find the pumpkin patch owner at once!" (he will be inside the cave...this time it wont be blocked so you can actually go into the cave) He would say "the walking pumpkins locked me in here...how are you in here?" "did they lock you in aswell?"
To escape you have to kill 50 pumpkin masks....And the pumpkin patch owner will thank you,But halloween is still ruined without pumpkins...But oh wait how lucky the pumpkin patch owner has some pumpkin seeds but you can only plant them in a special farm where you have to have farming mastered. You grow a pumpkin and then give it to the pumpkin patch owner. Reward.....will be a pumpkin mask?
To be honest, I don't really like this quest idea. Seems sorta boring and cliche. Also, I have already started planning a new quest for pumpkin mask. I'll try to incorporate maybe one or two ideas from this in (maybe the part about the mayor?), but other than that, this quest doesn't seem like it was planned well enough. Sorry.