Twelve-inch rung, it might be left in blanket covering the ground (8)
I believe the answer is:
footstep
'it might be left in blanket covering the ground' is the definition.
The definition suggests a singular noun which matches the answer.
'twelve-inch rung' is the wordplay.
'twelve-inch' becomes 'foot'.
'rung' becomes 'step' (I've seen this in another clue).
'foot'+'step'='FOOTSTEP'
Can you help me to learn more?
(Other definitions for footstep that I've seen before include "Mark made when walking" , "Sound of a pace" , "Sound of a step of someone walking" , "Sound of walker" .)