Plum Puddin' is a pony, a stout little gelding who pulls the cart Flora O'Leary drives to the market. Plum Puddin' was a bay, and a "good doer" meaning he was plump and shiny. He was generally a dour-tempered beast, but he gave Flora little trouble. Like any good Irish pony he knew a fairy woman when he saw one, and so he baulked when they met Peg o' the Sidhe on the road. Or maybe he was thinking of his stomach, because Peg had a gift for him.
‘See, the beast agrees,’ said the woman. She held out her hand to the pony.
‘What are you giving him?’ asked Flora sharply.
‘Nothing but an apple.’ The woman rolled her hand palm-up to show a slightly wizened fruit. Its sweet smell made Flora’s stomach twinge with hunger. The woman laughed like the tinkle of bells. ‘It’s nothing but an apple that grew on a mortal tree and was given to me by a lass named Apple Mary. See, the beast wants it.’
The pony gave her a nudge.
Flora shrugged. ‘Let him have it, if it came from Apple Mary. He’s a surly beast anyway, is Plum Puddin’.’
Puddin’ gave her a sly look under his forelock and crunched up the apple.
‘I’m guessing he won’t move a step from this place until I let you into the cart?’ suggested Flora.
The woman in green smiled and nodded. ‘You’d be guessing right.’
‘Up you go then,’ said Flora.
The woman set her foot on the step and next thing she was sitting in the cart. Flora stepped up with her long legs and settled herself beside her passenger. ‘Hup.’
The pony gave a nod and trotted on.
Plum Puddin' certainly knew which side his bread was buttered on!
You can meet him, along with Flora and Peg, in The Leapling and the Horseshoe Nail.