There have been alot of good theories about Big Mom’s devil fruit being either related to Witch-Craft or Acid but i wanted to go a litle bit deeper and share my ideas.
I agree with the idea that Big Mom’s power is witch-craft related but there are a couple of things i havent seen anyone talk about. I would like to start off with Big Mom’s ship.
The singing head looks like a cookie in my opinion. And its something Oda has hinted at before. Take a look at this Panel from Fishman Island.
Now if we talk about living cookies then ofcourse we have to link that to the Gingerbread man.
This picture from Shrek was the best i could find.
I believe Big Mom’s ability lets her turn Sweets, Cookies and Candies into living objects. This is similar to how Brook’s devil fruit works.
His soul emits a powerful “substance”-like energy which allows him to live. I believe Big Mom can also emit a substance-like energy which is her drool.
With this she can turn candies alive (if it enters the candy for example) which would explain her eating her crew (which were basicly candies or cookies). If we look at the panel where she eats them we have the crunching sounds (her eating cookies) and we see small parts falling down.
This substance, lets say her magic drool for now, comes from her stomach, which could be a witch’s cauldron.
Since Big Mom’s is most likely a paramecia this would fit in nicely.
Now this magic drool can also function without entering something and i believe Oda drew it next to the three-eyed girl.
(just a small note on the side: If the three-eyed girl is pudding it might be she is a adopted daughter and gets married against her will. It would be something a evil witch would do in my opinion, kidnapping kids, forcefully adopt them and them marry them off to increase her own influence. Which would basicly make pudding a hostage and Sanji the prince on white horse which goes to save her but thats a different topic).
Now if we take it the Blob thing (Magic Drool) is Big Mom’s power then we could also bring Ceasar into the mix. As we know Ceasar was asked to do research for Big Mom but he blew the funds somewhere else.
On Punk Hazard he had multiple things going on. First the SAD which is used to make Smiley Devil Fruits. Secondly the kids who he tried to turn into giants. And at last he had the gas weapon. Now the Sad was for Doflamingo, which later went to Kaido. The kids were basicly a old research project from Vegapunk for the World Government, which Ceasar made his own to proof he was better. And we know Jack bought his gas weapon in the past. Now Ceasar said he blew the funds somewhere else which means he didnt do the research Big Mom asked him to do. So what did she want him to research? I believe Big Mom was interested in the old version of the gas weapon. Ceasar used this version to destroy Punk Hazard four years ago.
Smiley was also made out of Blobs (really dont have a better word for it sorry).
Now what if Big Mom wanted Ceasar to give her power extra functions like for example the exploding when in contact with fire. We know Big Mom’s crew watched the experiment.
And when Ceasar was defeated they called Big Mom. But it could also have been because they figured he had not worked on her research orders but instead improved the weapon to turn into gas. This would explain them coming after Ceasar in Dressrosa.
These are just my thoughts on how Big Mom’s fruit might work. There are alot of things that can be linked to witch-craft but if Big Mom is a paramecia then it should still have something to do with her body. Her being able to food into living things might explain also why she wants candy so much. She can turn them into her own litle army just how Kaido is making a Zoan army. We know Blackbeard is out there hunting devil fruits and to make up the balance i believe Shanks is recruiting powerful Haki users like for example Rocksta who we saw with Whitebeard.
Hope you enjoyed the read!
*Theory by FrankyG