Hellscream takes the Beast Wars Cybershark mould and changes just about every piece you can remove from the basic toy. The pectoral fins are replaced with mechanical ones, moulded in a similar colour to the body, each containing a moulded harpoon. The dorsal fin is replaced by a dark green fin set into a coning tower. The hammerhead at the front now becomes a mass of mechanical parts , again coloured green, mounted on a notched blade missile. Like Cybershark's previous version the head can raise up above the lower jaw and be fired using the missile launcher in the shark's back. The tail and it's claw mechanism are gone to replaced by a large green four finned tail which looks like a propeller mechanism. The overall effect here is a shark crossed with a submarine but in the middle you can distinctly see Cybershark's body and this is one of the toy's main flaws: at the centre of the toy is a body that looks and is coloured almost the same as Cybershark, just without the green spots. It's almost like a bad kitbash: replace all the removable parts but leave the bit in the middle you can do nothing with alone. In fact it's a trivial exercise to pop the pectoral fins off and remove the nose & tail then replace them with the corresponding parts from Cybershark to give a toy that's essentially the original bar the dorsal fin.
Transformation: Remove the tail and the head. Transform as per Cybershark then "Pull the underside of the shark apart down the middle lengthwise and fold up to the sides. Fold the robot arms out 90 degrees at the bicep joint. Fold the legs and hips out under the shark's mouth. Fold the shark's head back at the robot's shoulders to form the robot chest locking the legs in place and exposing the robot's head.". At this point when Transforming my new Hellscream that I've just bought off eBay, with no instructions or box, that I got a shock: his left arm was missing from just above the elbow. But just before I got to eBay to complain it was missing I remembered what was supposed to happen. The top of the base of the tail has a socket that fits the 5mm peg on the elbow allowing Hellscream to use it as a built in weapon (see bellow). The Shark's head/blade weapon ends up held in his other hand - you can't really leave it on the chest it's just too big and (phallic Transformer watch) leaves the blade sticking out of his groin.
In robot mode there's been some changes too: the blue pieces (the same colour as the sharks body) that have been retained from Cybershark can be found in the same colours. All the pieces that were white before (with the exception of the now missing lower left arm) are now black. He has a new blue upper left arm, ending in a 5mm peg (see above) and a new green upper left leg. The dark green head is new but bears a resemblance to the old Cybershark head with lots of teeth and a 3 pointed crest. A Beast Wars Destron (Predacon) rub sign is found on the inside of the shark body which is now on his robot back.
Articulation is identical to before: bends at ankle and knee, swivels bellow a ball jointed hip, ball joints at neck and shoulder, bicep swivel and a bending elbow. He can still use his chest launcher to fire the head missile or either of the (now black) missiles in his back. He has a new missile launcher found in the centre of the end of arm rotor mechanism which will fire the missiles or the blade found inside the head. However keeping the head on the blade will restrict the missile from locking into place.
Of the four Cyberbeasts to take their forms from Beast Wars toys, Cybershark is my favourite base mould. Conversely he's my least favourite upgraded Cyberbeast (Dirge Gun > Thrustol > Max B > Hellscream) It's the large area of obvious original shark that's my big problem. None of the other three Beast wars originated Cyberbeasts toys have such a large area of original toy visible. A remould on these pieces would improve the toy no end.
Hellscream was numbered D-23 but doesn't appear in a VS set. Hellscream isn't repainted during the Japanese Beast Wars II line but Cybershark does have a later remould as Beast Wars Neo C-37 Sharpedge.
A viable alternative to paying for the original version which shows up less often than the other Beast Wars originated Cyberbeasts.