The final twist in the 2002 sci-fi horror Signs was a lot of fun, but the longer I think about it, the less it makes any sense. Part of the appeal of the M. Night Shyamalan movie is the number of unique factors that came together to save the protagonists in the end, putting an end to the plans of an invading alien species. Like many sci-fi stories, there are aspects of this that we have to accept despite their lack of sense. However, the older I get and the more I consider it, the harder it is for me to swallow the larger picture of Signs.

https://screenrant.com/signs-alien-twist-water-makes-no-sense/