Animated Entity textures? D:

Sorry if this has been asked here before- but, is it possible to have animated entity textures in a resource pack? Like, I know how to make an animated block texture. I know how to make an animated block entity texture (ender chests, to be specific, which aren't even animated in vanilla!), but when I try to animated an actual mob, like a Creeper, it just... doesn't. It behaves like an animated texture w/out an accompanying .mcmeta file (see below), even though there is a creeper.png.mcmeta file present in the correct space.
So, like, what gives? Is it just not a thing you can do, or am I missing something? D: