Otter
The otter's flexibility is genuinely impressive. Its serpentine spine allows for remarkable manoeuvrability in water, enabling sharp turns, backward somersaults, and the famous belly-up floating position. Studies from the Royal Veterinary College's Mustelid Biomechanics Unit have documented otters twisting their bodies up to 180 degrees whilst pursuing prey. They can adapt to freshwater, saltwater, and occasionally someone's ornamental koi pond with equal aplomb.
Time
Time's flexibility, once thought non-existent, was revolutionised by Einstein's relativity. Time can dilate, contract, and curve around massive objects with an elegance that would make any gymnast envious. Near a black hole, time slows so dramatically that watching an otter catch a fish would take centuries from an external observer's perspective. The Cambridge Relativistic Studies Group notes that time is 'considerably more bendy than previously assumed, though still fundamentally committed to moving forward.'
VERDICT
The otter's physical flexibility is undeniably charming, but time's ability to literally warp the fabric of reality represents flexibility on a cosmic scale. When your competitor can stretch near infinity, a flexible spine seems rather quaint.