A man murdered his girlfriend's 17-month-old baby in a "deliberate and vicious" attack, a Cardiff Crown Court has been told.
Finley Thomas was found motionless and looking "ghostly" in colour by paramedics at his home in Tonypandy.
The jury heard his mum said Finley had fallen down the stairs
Boyfriend Sean Buckley, who's 28, has pleaded not guilty to one count of murder.
He has also denied one count of causing child cruelty - a charge also denied by Finley's mother Chloe Thomas.
The court heard Chloe Thomas made a 999 call and told the operator that her son had "banged his head" and was "lying floppy".
Finley was first taken to the Royal Glamorgan Hospital before being transferred to the University Hospital of Wales, Cardiff.
He died the following day.
The prosecution said a post-mortem later revealed Finley had several other injuries - including rib fractures and a fractured skull.
It also highlighted a report made by a consultant paediatric radiologist, saying Finley's injuries could have been caused after being shaken and thrown or from "multiple impacts".
Mr Buckley and Miss Thomas both deny the charges.
The trial is expected to last six weeks.