All the other new tonics can be used while already transformed to switch / cycle transformations fast. You can even switch to the bells while transformed (breaks transformation).
Doesn’t work with the Halloween tonic though, if you try to use it while being transformed with any of the new tonics, you will get just get the “can’t use it while transformed”-message.
Same when trying to use any other tonic or other items like the bells while transformed as any of the halloween creatures, you can’t use any of them.
Please adjust the behavior so all of the tonics behave the same.