Returned and Relocated

Me: You know, scythes were designed for reaping grain, not combat. Yes it is bladed so it could be a weapon but not a very efficient one.

Scythe Wielder: *Does that badass scythe stuff*

but that looks nothing like Goodra

Understandably, It’s probably because the Glaucus atlanticus is really well known, i.e. it IS the dragon slug you first think of when you hear the words dragon + slug.

However, confusingly (and wonderfully)  there is another group of aeolid nudibranch sea slugs called blue dragons, the Pteraeolidia 

Which not only match Goodra’s colour scheme excellent but are called dragon sea slugs too!

Another closely related group also looks like our fave gooey dragon, the Phyllodesmium sp.