Lincoln Crown Court heard Paul Robson sparked a nationwide manhunt when he spent four days on the run last month after fleeing North Sea Camp on a prison bicycle.
Robson, 56, was serving a life sentence for sexually assaulting a woman at knifepoint.
He was jailed for eight months after admitting a charge of absconding.
Robson was transferred to the category D prison in late January, the court was told, and was reported missing on 13 February after the dummy was found on his bed at the Lincolnshire jail.
He was later arrested in the seaside town of Skegness after being spotted by a member of the public.
Open prisons like North Sea Camp, otherwise known as Category D, have the lowest security levels
The court heard Robson had spent much of his sentence at HMP Whatton in Nottinghamshire in a single cell, where he had been engaged with artwork and meditation as part of his Buddhist faith.
Michael Cranmer-Brown, mitigating, said following the move to Lincolnshire he found himself sharing a cramped cell with another inmate who “played on his Xbox all day”, and he was unable to meditate or do any art.
“He was advised to a do a jigsaw on his bed,” Mr Cranmer-Brown said.
Robson did not want to be moved, but had no choice in the matter, he added.
On the night of the escape, Robson had waited until his cellmate was asleep and climbed out of the window after leaving the dummy in his bed.
Mr Cranmer-Brown said Robson made his way to Skegness because he had been brought up in a seaside resort.
Passing sentence, Judge Simon Hirst told Robson his eight-month jail term for the escape would run alongside his life sentence.
Robson will not be eligible to apply for parole for at least a further two years.