Tywod! Môr! Mwydod! Mae Porthoer wedi'i orchuddio â mwydod. O ble ddaethon nhw? Sand! Sea! Worms! Porthoer is covered in wriggling worms. Where did they come from?
7 o ddyddiau ar ôl i wylio
11 o funudau
Gweld holl benodau Ger a Gu
