Deathclaw

Deathclaws are creatures found after the war.

Background
The creatures are mutated Jackson's Chameleons, who group together with a pack mentality. Some wastelanders consider deathclaws to be mythical creatures, vampires, or ghosts. Those who have seen them describe the creatures as extremely dangerous, fast, with tough hides and sharp claws. Deathclaws can throw objects, slam the player character into the ground or stagger them. Behemoths are the only creatures mentioned as being more of a threat than deathclaws.

The creatures lay eggs, pairings decided by the pack leader. Hunters are unable to prevent deathclaws from establishing nests, which disrupts trade routes. The only way to disrupt the nests is to kill the pack mother.

The Appalachian Enclave's research division noted that the genetic manipulation looks similar to their own projects. The Enclave also used deathclaws in their experiments at Raven Rock.

The deathclaws created by the Enclave in Vault 13 are known as Intelligent Deathclaws, modified in an effort to create expendable soldiers. The creatures were injected with FEV by the Enclave, resulting in their increased intelligence. They realized they were destined for slavery, utilized by the Enclave for soldiers, and "played dumb" until they could gain their freedom. The Enclave realized the deathclaws had gained more intelligence than intended, and plan to exterminate the group. Goris, the son of the Vault 13 pack leader Gruthar, is a recruitable companion.

Behind the scenes

 * Scott Campbell shared that the initial design for the deathclaw in Fallout was that of a very furry FEV-hybrid of wolverine and brown bear, which was later replaced by the model of a Tarrasque which was produced for Planescape: Torment, but ended up being unused. Chris Taylor also stated that the hairy version was canceled due to technical limitations at that time, with the original concept being later revived for Fallout Tactics.
 * The Fallout Bible contains background information regarding the development of deathclaws.
 * The Fallout 4 deathclaw model was made by Jonah Lobe. Lobe started working on a model in ZBrush from home, referencing his deathclaw models from Fallout 3, while also taking inspiration from lions for their eyes. Lobe showed the model to Todd Howard when it was about 70% done, and Howard gave him the go-ahead to finish it. Two days later, Howard returned to Lobe's office cube and informed him that they were restructuring the demo to include a final power armor versus deathclaw battle, which became part of When Freedom Calls in the final game.
 * A Fallout 4 deathclaw appeared in an advertisement for the PlayStation Now service, where it appeared alongside a cast of characters from various video games, including Liberty Prime.