Atomistic simulations are performed to investigate the interaction between prismatic dislocations and {112¯2} twin boundary in hexagonal close-packed titanium. Very unusual and interesting dislocation transmutation is observed. When a (101¯0)13[1¯21¯0] dislocation interacts with the twin boundary, it is first transmuted into a (011¯2)13[21¯1¯0] dislocation in the twin. But the (011¯2) is not a common slip plane and the transmuted dislocation is unstable which is then further transmuted into a prismatic dislocation (011¯0)13[21¯1¯0] in the twin with a lower line energy. This behavior, along with the transmutations of other prismatic dislocations, can be understood from the perspective of lattice correspondence in deformation twinning.