Clamperl can only evolve into Gorebyss if you give it a Deep Sea Scale to hold and then trade it.
trade clamper with a deepseatooth or a deepseascale dst:huntail dss:gorebyss.
You take it to the researcher in the bridge of the abandoned ship, and he will then tell you to take it Captain Stern in Slateport City (At the ferry depot). Stern will then offer you a Deepseatooth or Deepseascale which you can use to evolve a Clamperl into a Huntail or Gorybess, respectively (I would recommend Gorybess, good special attack and access to ice beam and psychic, and maybe hidden power electric).
Clamperl when traded
you can evolve a clamperl to a huntail by trading it ween it is holding deepsea tooth or you can evolve him or her by trading it with deepseacale to a gorbiss with is a ex-treame ly rare pokemon!
Give the deepseascale to clamperl and trade and trade back and it will evolve into a huntail. Give the deepseascale to clamperl, trade and trade back and it will evolve into a huntail.
give it a pearl .
It can by trading it while holding a deepseascale or deepseatooth.
Gorebyss- trade a Clamperl that is holding a Deepseascale Huntail- trade a Clamperl that is holding a Deepseatooth Mismagius- Evolve a Misdreavus with a Dusk Stone Honchkrow- Evolve a Murkrow with a Dusk Stone
You must have a clamperl and let it hold the deepseatooth/deepseascale. Then, trade clamperl. If clamperl is holding the deepseatooth,it will evolve to Huntail. If it was deepseascale, it will evolve to a Gorebyss.
A deepsea tooth is a tooth that makes clamperl evolve into huntail when the clamperl is holding it and is traded into anouther persons game. There is also a deepseascale which makes clamperl evolve into gorebyss in the same manner.
The DeepSeaTooth is a hold item, capable of evolving Clamperl. To use it, have Clamperl hold the item, then trade the Pokemon. When it arrives, it should evolve into a Huntail. Alternatively, if you trade a Clamperl with a DeepSeaScale, it will evolve into a Gorebyss.
Shaymin does not evolve in Pokemon Diamond.