Old Man Willow

In J. R. R. Tolkien's legendarium, Old Man Willow is a fictional character, appearing in The Lord of the Rings. He was a willow tree in the Old Forest from which much of the Forest's hatred of walking things came. He is portrayed in the story as a tree, albeit a sentient and evil one with various powers including irresistible hypnosis and the ability to move his roots and trunk. Some characters of the story speculate that he may have been related to the Ents, or possibly the Huorns, as the Old Forest was originally part of the same primordial forest as Fangorn. However, unlike Ents or Huorns, Old Man Willow is portrayed more like a tree, with roots in the ground, and without the ability to uproot himself and move from place to place.

Tom Bombadil had power over Old Man Willow, and checked the evil as much as he could, or was willing.

The Fellowship of the Ring
Old Man Willow casts a spell on the hobbits (Frodo, Sam, Merry and Pippin), causing them to feel sleepy. Merry and Pippin leaned against the trunk of the willow and fell asleep, while Frodo sat on a root to dangle his feet in the water, before he also fell asleep. The willow then trapped Merry and Pippin in the cracks of its trunk and tipped Frodo into the stream, but the latter was saved by Sam, who, suspicious of Old Man Willow, managed to remain awake. After Frodo and Sam started a fire out of dry leaves, grass, and bits of bark in an attempt to frighten the tree, Merry yelled from the inside to put the fire out because the tree said it was going to squeeze them to death. They were saved by the timely arrival of Tom Bombadil who 'sang' to the ancient tree to release Merry and Pippin. The tree then ejected the two hobbits.

Background
According to Tom Bombadil, long ago at the dawn of time in Middle-earth, long before even the Awakening of the Elves, trees were the only inhabitants of vast stretches of the world. Because the Elves awoke far in the East, it was still a considerable time before any other beings spread into the vast primeval forests of western Middle-earth. A handful of trees survived from this time until the present day, who are angered at the encroachment of Elves and Men and their dominion over the earth; trees who bitterly remember a time long ago when they were as Lords of vast regions of the world. Bombadil relates that of the corrupted trees of the Old Forest, "none were more dangerous than the Great Willow; his heart was rotten, but his strength was green; and he was cunning, and a master of winds, and his song and thought ran through the woods on both sides of the river. His grey thirsty spirit drew power out of the earth and spread like fine root-threads in the ground, and invisible twig-fingers in the air, till it had under its dominion nearly all the trees of the Forest from the Hedge to the Downs."

This description and its context make it clear that the Great Willow was originally a tree, despite its evident malicious sentience and power.

Old Man Willow is also shown as trapping Bombadil himself briefly, in Tolkien's narrative poem The Adventures of Tom Bombadil.

Portrayal in adaptations
Although this scene did not appear in the 2001 movie adaptation, a very similar episode with hobbits being swallowed by a tree was included in the extended DVD edition of the second film where Merry and Pippin are attacked by a Huorn in Fangorn forest. In this interpretation Tom Bombadil's lines are spoken by Treebeard.

Old Man Willow is a featured boss in the 2002 game The Lord of the Rings: The Fellowship of the Ring. Here, playing as Frodo, the player must hit Old Man Willow's trunk with rocks from a distance while avoiding his swinging willow switches until Tom Bombadil arrives.

In the MMORPG Lord of the Rings Online, a quest to gather lilies for Goldberry at the foot of Old Man Willow is given to the player by Bombadil, who warns that the tree will "sing you right to sleep".

Song inspiration
A song called "Old Man Willow" by the band Elephant's Memory describes the anger, frustration, and resentment resulting from the curse of having to live an entire lifetime rooted in one spot while the world goes on all around. It appears in the soundtrack of the critically acclaimed film Midnight Cowboy.