The sound of effortful heavy breathing.  Bilbo with his short little legs puffs along the passage – and even the draught of air in Chapter 13 which could have blown out his light only threatened to puff it out.  Definitely funny and low.

• 01.038 he thought as he puffed along the passage.
• 01.095 and puffing on the mat,
• 02.020 Very puffed he was,
• 07.087 gasped Bombur puffing up behind.
• 08.055 gasped Bombur puffing up behind.
• 08.125 puffing and panting
• 12.027 puffing and blowing while the ropes creaked
• 13.008 and they made a deal of puffing
• 13.023 but it almost puffed out his light.