. . . on the flat among tall trees growing in scattered fashion in the grasslands, when Frodo said: ‘I can hear a horse coming along the road behind!’

They looked back, but the windings of the road hid the traveller.

‘I think we had better get out of sight,’ said Bingo; ‘or you fellows at any rate. Of course it doesn’t matter very much, but I would rather not be met by anyone we know.’

They ran quickly to the left down into a little hollow beside the road, and lay flat. Bingo slipped on his ring and sat down a few yards from the track. The sound of hoofs drew nearer. Round a turn came a white horse, and on it sat a bundle – or that is what it looked like: a small man wrapped entirely in a great cloak and hood so that only his eyes peered out, and his boots in the stirrups below.

The horse stopped when it came level with Bingo. The figure uncovered its nose and sniffed; and then sat silent as if listening. Suddenly a laugh came from inside the hood.

‘Bingo, my boy!’ said Gandalf, throwing aside his wrappings.

 

                           J. R. R. Tolkien, 'The Return of the Shadow" (1988), p. 47
                          Vol. 6 of The History of Middle-earth, ed. C. Tolkien