Touch this plant's leaves and they fold shut in under a second

Mimosa pudica, the 'sensitive plant', collapses its leaflets and droops its stem within a second of being touched, using rapid water shifts in specialized cells rather than muscle or nerves. Researchers have shown it can even learn to stop reacting to a harmless repeated touch, and remember that for weeks.

— Wikipedia contributors, Mimosa pudica — Rapid plant movement and habituation studies