@@ -20 +20 @@
-<gloss>two-tailed cat yōkai</gloss>
+<gloss>fork-tailed cat yōkai</gloss>

https://mag.japaaan.com/wp-content/uploads/2017/10/nekomata-1280x720.jpg

I'm suggesting this correction because the current meaning can be misinterpreted as the cat starting off with two tails (as some sort of birth defect), which instead are a result of the transformation of an old cat into a Nekomata. When the cat transforms (because of old age), then the tail splits. Also the current meaning could be interpreted as the already Nekomata (because of the two tails mentioned before) being able to further transform itself into a terrifying creature, but I haven't found any reference for that in the japanese wikipedia page in the section about the "house cat Nekomata". All I've found is that it either deceives (老いたネコは『猫股』となって人を惑わす) or brings harm to humans (飼い猫も年を経ると化けて人を食ったりさらったりする). 
Some nekomata depictions in the ref. above.

@@ -20 +20 @@
-<gloss>yōkai believed to be an old fork-tailed cat that can transform itself into a terrifying creature</gloss>
+<gloss>two-tailed cat yōkai</gloss>

OK

@@ -20,0 +21,5 @@
+</sense>
+<sense>
+<pos>&n;</pos>
+<field>&jpmyth;</field>
+<gloss>giant beast that inhabits the mountains</gloss>

in response to >> I'm not seeing the mountain part.
from the previous daijs link, it says "山中に棲む巨大な獣" and in the previous wikipedia link it says "山の中にいる獣といわれるもの".
Essentially there are two different version of what a nekomata is, one is an old house cat that with age turns into a nekomata, the other one is a beast that lives in the mountains to being with