Inflation spell

Hello
I am curious if there is any inflation spell that's actually works. I tried the goo summon about 3 times now and I think there are some effects but I can't say if I only imagine them.

What exactly do you mean "inflation spell". Are you talking about a spell to blow up like a balloon or something else entirely?

I talk about something to make me blow up like a Balloon and stay at this level or just a simple weight gain. For me it's hard to gain weight because I have a very strong metabolism

No these spells aren't real and they won't manifest results.
Any results you are seeing from an inflation spell are merely effects of a placebo.

Is there any possibility to help gain weight besides to eat more?

A spell can assist, but a spell itself won't be able to do anything alone, you would still need to increase your calories and do the munane efforts alongside the working.