Adults of A. childreni grow to a total length (including tail) around 1–1.5 m (3–5 ft).
The scales on the top of the head are enlarged, while those on the upper surface of the body are small and smooth, with a rainbow sheen that can be seen when exposed to direct sunlight.
The upper surface of the snake is brown with darker spots in five or six longitudinal series.
A dark streak on each side of the head passes across the eye.
The lips are yellowish, spotted with brown.
The lower surface of the snake is uniformly yellowish.
The head of the snake is distinct from the neck.
The nostril is superolateral, pierced in a large semidivided nasal scale.
The eye is moderate in size, with a vertical pupil.
The body is slightly laterally compressed.
The tail is short.
About 41 to 45 rows of dorsal scales cross the snake's back, and 257 to 287 ventral scales are seen along the lower surface.
A single undivided anal scale is found immediately in front of the anus, and 38 to 53 subcaudal scales are on the lower surface between the anus and the tip of the tail, all or mostly in two rows.

The rostral is broader than high, barely visible from above.
The internasals are slightly longer than broad and are shorter than the anterior prefrontals.
The second pair of prefrontals is in contact at the midline, or is separated by a small shield.
These posterior prefrontals are sometimes broken into several shields.
The frontal is one and a half  times as long as broad, slightly shorter than its distance from the end of the snout, longer than the small parietals.
Three to 10 small loreal shields are present, some almost granular, with 11 to 13 upper labials.
Three or four of the posterior lower labials have deep pits.

The anterior maxillary teeth and anterior mandibular teeth are very long, gradually decreasing in size posteriorly.
The premaxillary bone also has teeth.
Adults of A. childreni grow to a total length (including tail) around 1–1.5 m (3–5 ft). The scales on the top of the head are enlarged, while those on the upper surface of the body are small and smooth, with a rainbow sheen that can be seen when exposed to direct sunlight. The upper surface of the snake is brown with darker spots in five or six longitudinal series. A dark streak on each side of the head passes across the eye. The lips are yellowish, spotted with brown. The lower surface of the snake is uniformly yellowish. The head of the snake is distinct from the neck. The nostril is superolateral, pierced in a large semidivided nasal scale. The eye is moderate in size, with a vertical pupil. The body is slightly laterally compressed. The tail is short. About 41 to 45 rows of dorsal scales cross the snake's back, and 257 to 287 ventral scales are seen along the lower surface. A single undivided anal scale is found immediately in front of the anus, and 38 to 53 subcaudal scales are on the lower surface between the anus and the tip of the tail, all or mostly in two rows.
The rostral is broader than high, barely visible from above. The internasals are slightly longer than broad and are shorter than the anterior prefrontals. The second pair of prefrontals is in contact at the midline, or is separated by a small shield. These posterior prefrontals are sometimes broken into several shields. The frontal is one and a half  times as long as broad, slightly shorter than its distance from the end of the snout, longer than the small parietals. Three to 10 small loreal shields are present, some almost granular, with 11 to 13 upper labials. Three or four of the posterior lower labials have deep pits.
The anterior maxillary teeth and anterior mandibular teeth are very long, gradually decreasing in size posteriorly. The premaxillary bone also has teeth.
Children's python