I really need to know!!! help please!!!!
Is this for a paying customer?
Yes, its for a paying customer
OK, to answer the question, you could likely use balloon lights. They are very small.
Secondly, Avengers is a copyrighted image, so the only way you can make the cake legally is to get permission from the copyright owner. This is always a problem when doing cakes that replicate characters, logos, etc.