Disclosed is an apparatus and a method for removable of undesired material from body lumens. The apparatus may be used for fragmenting or removing a thrombus or occlusion from a blood vessel. The apparatus includes first shape segments and second shape segments connected to form a coiled member. A longitudinally extending tether is positioned inside the first shape segments and outside the second shape segments along the length of the coil. Applying a proximal force on the tether produces a change in the shape of at least a portion of the coil from a first generally linear configuration to a second complex three dimensional shape. A method of using the apparatus to engage and remove, or fragment, the thrombus or occlusion is disclosed.