Altogether, it looked quite different from a branch of the sycamore, or anything belonging to the tree.
Once or twice, while Caspar had his eyes upon it, he thought or fancied that it moved; but not being sure of this, he said nothing, lest the others might laugh at him.

It would not have been the first time that Karl, from his superior knowledge, had indulged in a laugh at his brother's expense.
Caspar's attention being now engrossed by the peculiar appearance he had noted, he continued to scrutinise it; and soon perceived that around the curved excrescence there was a circular disc some eight or ten inches in diameter, and differing in colour from the bark of the sycamore--by being many shades darker.

This disc appeared composed of some substance that was not ligneous: for it no more resembled wood than the curved ivory-like object that protruded from its centre.

Had Caspar been asked what it did look like, he would have answered that it resembled the agglutinated mud used by swallows in building their nests--so like it, that it might have been the same substance.
Caspar continued to scrutinise these two curious objects--the tusk-like excrescence, and the dark disc from which it protruded; and not until he became fully aware that the former had life in it, did he communicate his discovery to his companions.

Of this fact he was convinced by seeing the crescent suddenly disappear--as if drawn within the tree, while in its place a dark round hole was alone visible.