I have only encountered this group of aliens once as far as I know.
They are gentle and kind. They seem to have an interest in humans and at one point fought to be the first alien race to present themselves to us.
They are round bodies with no noticeable appendages except for a long, narrow tapered neck that ends in an elongated round head. (Imagine a drop of water turned upside down)
Their skin is a uniform, medium blue. The only features I could see on their faces where a black ring that raised from the skin and surrounded a similar white ring. Both moved and changed shape when the aliens spoke. The rings moved sort of like rubber bands.
They wore white hooded robes that covered their heads and draped over the globular bodies. The closest description I can think of is a duck pin bowling pin.