A boy left his bike chained to a tree when he went away to war in 1914. He never returned, leaving the tree no choice but to grow around the bike. Incredible that this bike has been there for 98 years now!
This bike, aka the "tree that ate a bicycle" on Washington's Vashon Island, has its own Snopes page (I won't spoil if this story's true): https://www.snopes.com/fact-check/bicycle-tree/
That was my first thought! Buck tweed bicycle!