A sand-fairy, as invented by E. Nesbit for a trilogy of children's novels, in the first of which, "Five Children and It", the psammead is the it. From that first novel: "eyes that were on long horns like a snail’s eyes, and it could move it in and out like telescopes; it had ears like bat’s ears, and its tubby body was shaped like a spider’s and covered with thick soft fur; its legs and arms were furry too, and it had hands and feet like a monkey’s�?.
From Wikipedia: The Origin of the Psammead: The five children find the Psammead in the gravel-pit, which used to be seashore. There were once many Psammeads but the others died because they got cold and wet. It is the only one of its kind left. It is thousands of years old and remembers Pterodactyls and other ancient creatures. When the Psammeads were around, they granted any wishes, mostly food for the families. The wishes would turn into stone at sunset if they were not used that day, but this doesn't apply to the childrens' wishes because what they wish for is so much more fantastic than the wishes the Psammead granted in the past.
The creature is frighteningly ugly, bad-tempered and is quite malicious, as it deliberately abuses the wishes the children make, causing the results to be alarming and unexpected. The children quickly regret meeting the creature, yet their desires to make more wishes push aside their qualms about the Psammead.
The name Psammead, (pronounced “Sammyadd�? by the children in the story) appears to be an inventive Greek pun coined by Nesbit (from the Greek ψάμμος "sand" after the pattern of dryad, naiad, oread, etc.) upon the name of “Samyaza�? the leader of the Grigori (“Watchers�?, from Greek egrḗgoroi) supernatural creatures of antediluvian myth. Knowing the pun's in-joke, shows the logic at work behind the creature's phobia of water “nasty wet bubbling sea�?, and why the eyes are placed watchfully upon the end of long horns like a snail's eyes.