So, the topic is favorite animal, insect, vermin, or arachnid, and I chose instead to go for my favorite Magical Beast, which is darn close to being an animal.
The Displacer Beast:
I like them because they are sneaky. They live in multiple dimensions, and so hitting them can prove difficult. I like them because they have tentacles, but also because they are like cats. They are one of the iconic D&D monsters that have just found their way into my heart without me being able to really delve into the real, solid reason why I like it. Maybe “just because” is a good enough reason?
I’m not a huge fan of unintelligent animals in D&D, partially because most monsters are opposition for the party, and I really dislike the idea of adventurers kick-circling an innocent animal. Even a deadly one. I’d rather set them on the trail of something or someone with an evil plan instead of something that is really just looking for something to eat. While I will use animals as opposition from time-to-time, I tend to do so sparingly.