that is, it is just strange enough to be believable.

The middle pic just looks like ordinary Terran jellyfish.

The top picture looks like an earth frog head on a body equipped with shoulders, hips legs and arms jointed much like a primate, that is, ankles, wrists, knees, feet arranged pretty much like ours. The head is all wrong, though. It is too human in arrangement: two eyes above and on either side of a nose and a mouth (with an up-down jaw) below. It is hard to tell if that thing on the right side of its head is another eye or perhaps an ear, and if by symmetry there is another on the left side.

On our own world, there are many examples of distantly related organisms having similar body plans and organ structures. After all, some anatomical arrangements are very suitable for specific environments and are likely to appear over and over again in different planets. For example, plesiosaurs, fish and cetaceans have very similar shapes. On other worlds we may indeed find many creatures with body plans very similar to those found on earth. Still, too many of our aliens still are too humanoid in appearance. There is no reason intelligence must always arise in arboreal creatures adapted to savanna habitats.

What about intelligent termites? Or even cephalopods. The human arrangement is evolutionarily reasonable, but there is no reason it has to be that way everywhere, all the time.

Google some of the images depicting Larry Niven's "Pierson's Puppeteers".