The minicon socket is halfway down the truck on the underside. Although as an add-on it looks like it's vehicle mode the two arms add something to the feel of the larger toy.
To TF: fold the back half of the crane down under the front half revealing the head. Fold the front of the cab up, then fold down the entire cab to become the feet. Rotate 90 degrees at the waist.
Nice robot mode has entombed the back wheels in the middle of the chest - nice touch. The grabber becomes his right arm and the crane hook his left. He's got bending knees & hips - separated by legs cast in dark blue like Overcast's body, a waist that turns and shoulders that turn & pivot to the sides.
Decent Minicon, oddly reminiscent of Bonecrusher from the Land Military team.
Longarm was sold in the Giant Planet Minicon team pack with Overcast & Deepdive.
The team reuses the names of three servants of Unicron in the original Transformers comic: Hook (Longarm), Line (Overcast) and Sinker (Deepdive) The name Hook is almost inevitable really for this mould, though it would have worked better for his original colours ! Green becomes yellow, purple becomes grey, blue becomes purple and grey becomes black. Now the yellow and grey here are very reminiscent of another member of the Land Military Team - this time the Dimension-X version of Wreckage, Shot.
Nice repaint.again. Interestingly although Deepdive is also repainted for this promotion, Overcast isn't !