Marshmallow Shield

One downfall (for me) is that it takes some time to construct properly. The visualization is simple, but it just requires a lot of energy. Basically, you want to picture a thick (probably at least one foot) wall of goo. Use semi-melted marshmallows for visualization. If you construct it in layers (which I do sometimes, to make it easier), you'll want to make sure the layers melt into each other completely - they can be a pain and separate on their own sometimes. You might want to put some Bubble Shields on the outside and inside of it if you're making it really gooey. It should hold it's own shape for some time, but it might require some maintenance depending on how you make it.

As I stated above - it can take a while to make, even if you are somewhat skilled. It's not particularly good at handling sharp objects, but it's not meant to be used as the only line of defense. Combine it with other defensive shields to provide better protection. After it's made it can be repaired somewhat easily, so you can keep it up for long periods of time.

One shield that can be combined well with the Marshmallow Shield is the Force-Bubble Shield. It takes longer to construct, but provides some of the best protection.