Two comments about the image - firstly, you can see the outline of craters through it. Secondly, it impinges on the silhouette outline of the window.

So, either it is a partially-transparent UFO trying to climb into the LM through the window, or it is an internal reflection. Given there are numerous other examples of unambiguous internal reflections in the Apollo record, I would be inclined to lean that way.

__________________
"I'd take the awe of understanding over the awe of ignorance any day." - Douglas Adams