Currently I have a campaign where the highly capable antagonist has a weak spot: A very beautiful, highly intelligent, jocund and unfortunately pretty spoiled raven which is also able to speak. The antagonist is forced to leave his home and I expect that the players will...erm..."visit" his house and find the bird.
In preparation I asked myself how the raven will react to the group and how to best play him (I wondered e.g. if birds are able to cry for manipulating others and the answer is that at least normal birds cannot do that). This developed into a general question:
Do you have any hints how to play convincingly the interaction between the player characters and intelligent non-humanoids (Humanoid = looks like a human with modifications: other head (Illithid, Orc), an attachment (tail, third eye) or whatever) ?
Do you or your players care at all ?
I also mastered horror adventures and I also asked myself how I can best transmit the alienness of a monster which cannot (or will not) speak together with the revelation that this thing is capable of understanding human behavior.