Old Man Willow - The Fellowship of The Ring

In The Fellowship of the Ring, Old Man Willow cast 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.