A Werewolf for the snowy biome

I was playing on a server with some friends, and I was traveling to a friends house, he was in the middle of the blizzardy mountains. It may have been night time, or nearing night time, though I could see well.  Honestly I felt a sense of enclosure and comfort. So I was in a valley between two hills or mountains, snow pouring down, walking across the frozen rover. I then thought I saw something, looking partially up, a black figure moving very fast jumped from one side of the ravine / gap to the other, it jumped right over it. I think it would be cool for there to actually be things like that. But maybe only in the snow biome, when its snowing at night. Or maybe then but also when the moon is full, does the moon change? it should. Anyways, black, fast, can jump high/far. Like a large humanoid dog. Maybe it has red eyes. killing it could give you something like werewolves fur or werewolves blood or heart or venom, and those have some special effects. Also I'd appreciate it if better AI was built for mobs. They should be able to place and break blocks to get someone, have planned group attacks, etc. A builder villager would be cool, builds houses.  Add more complexity to things. Cool end forest like I've seen a mod of. Natural primitive indigenous tribes. etc.