Tankentai.How to make a kamehameha?

Hey i am using tankentai,and one thing i really dont know how to do is a blast.

Like Goku's Kamehameha.

I wanted the character go to the same Y axis as the monster and then shot a blast similar to kamehameha.

How would i do it?

Creating a animation or using a sprite and stretching it to the left or it is impossible to do it?

Thanks in advance.