The known facts are these. Ed Clements had a messy room. This is how messy the room was: Ed had a pet lizard, whom he lost, in the room, and found not sooner than one full year later--still alive.
Now.
The name Clarence, in Clarence's own ears, does not bring to mind rounded spectacles and mildness. Clarence means silent creeping warrior, defiant fugitive from the gods, terror of insects everywhere, the Lizard Whose Fate Is of His Own Making. Some are gods, and some are prey, but between them there is only Clarence.
Clarence is fearsome. His scales are smooth and green and tough, interwoven in graceful, hypnotic patterns all over the surface of his body. His head is long and his eyes glitter with certainty. His limbs move with perfect precision and power. He is not the terror of insects; only one insect at a time can ever learn of his existence, and then that one tells no tales. Once he has chosen his target, spotted a fly or a cockroach at unawares, and said to himself, "I shall eat that creature," Clarence strikes with blinding speed, moving in the blink of a faceted eye from outside his victim's awareness to a cruel and viselike pinion from which there can be no escape. He is mighty.
There are no regions of the world he does not wander, save one. His claws find hold in any surface, he can climb the sheerest walls, all but one. He has gone sometimes to the very threshold of that place, the cage of unscalable walls where once he himself was captive of the gods.
Time out of mind Clarence was held by the walls, allowed to run only the length of one stick, one small bowl of water, the narrow confines of the glass prison. Tame yellow crickets were thrown inside for him to eat, and he toyed with them, as they could run no further than could he. Outside lay the vastness of the world, visible through the walls, but only on rare occasion was he lifted by divine hands out of his prison, and his every dash for freedom was checked by their intercession. Time out of mind this was his life. At last the day came when Clarence was left to run the sweeping plain of the bed, while the god who kept him sat unwary at a distance. All around the edges of the plain Clarence crept, furtive, desperate, until at last he found his bridge: a sloping pile of fabric, tangled and wrinkled, that reached almost to the surface where he ran.
Quick as thought Clarence leapt, landing silently in a crevasse of flannel. He forced his way ever downward, though the path turned and folded beyond measure. At last he emerged from the pile into the open air, the bed left far above him, and the god still aloof and unsuspecting. Before Clarence lay a perilous stretch of bare carpet, the unadorned bedrock that lies always at the very lowest nadir of the shifting world. But after this was the wilderness, and safety. Clarence is swift; he reached the haven of the wilderness faster than any living being could follow, and fearless he pressed deep into that unknown, even when the booming voice came calling out Clarence, Clarence behind him.
Now Clarence knows the wilderness. He is its keeper. The wilds change, caverns and tunnels that once he knew may vanish abruptly or turn in upon themselves, but Clarence knows their ways, and he cannot be found. From time to time, when he climbs out of the caverns and walks the utmost crests of the wilderness, his gaze reaching to all horizons, it happens that his old keeper will be in sight. Then he must dive below, dash and scramble to some faraway place, to avoid the attention of that being, who would surely try to recapture him if ever he chanced to see. But this cannot come to pass. That same shocking speed that forever seals the fate of Clarence's prey suffices to carry him far out of his own peril in the briefest of moments; Clarence can never be found against his will.
From time to time his travels have led him again to the prison, which yawns still in readiness for his return, but he will not enter.
Or:
Clarence and Ed are friends. Ed visits the room where Clarence lives all the time, and when he comes he brings things that are good to eat, or things that are fun to play with and run around on. Sometimes Ed picks Clarence up, and Clarence runs around on his shoulders, or up into his hair.
For a while, now, Ed hasn't picked Clarence up so much any more. Instead he lets Clarence run around all over the room, which is a lot more fun than running around in the glass box where Ed used to put him down most of the time. Now Clarence climbs over and under stuff all day. Ed still comes to visit, and he still leaves things for Clarence that are good to eat, only now he leaves them on the floor instead of in the box. Clarence is grateful to have such a good friend.
Once in a while, when Ed is asleep on the bed, and when something is lying next to the bed that Clarence can climb up on, he settles down next to Ed's forehead, to visit. Once in a while he climbs in his hair, but he's noticed that this usually makes Ed roll over, which is dangerous and means Clarence has to jump out of the way. So now, when Ed sleeps, Clarence just sits next to him for a while, blinking, and listens to his friend snore.