It seems noone has posted this until now. There is a fusion(merge) sequence at the end of an anime movie called "
Origins: Spirits of the Past", also known as "
Gin-Iro no Kami no Agito". Even though I am not fully sure about what happens, two spirits of nature merge into a form of a human girl that seems somewhat like mother Earth. Here is an AMV clip I found on Youtube that shows the sequence in fast speed.
(0:59-1:02)