Swan

Swan, born Edgar Swann, is a unique super mutant behemoth living in Swan's Pond, the center of the Boston Common in 2287.

Swan rises from the Boston Common pond to squash anything that comes too close or makes the mistake of shooting the thick armored shell he fashioned for himself out of fragments of swan boats.

Background
Rather than a random monster, Swan was once Edgar Swann, a low level Institute worker who found himself on the wrong end of the law after stealing a couple of cigars. This all occurred around 2178 as the Institute was first developing its organic slave race. During the trial, he was offered a choice of participating in the FEV experiments that just started. Originally presented as "probation," Edgar was provided with food, water, shelter and infected with the Institute's own strain of FEV. Within six days, his body began to remake itself, leading to constant ache and disorganized thoughts as the strain forced the changes.

Two weeks later, the evolution stabilized, with a threefold increase in muscle mass and major increase in intellectual capacity: In short, a full success. Swann even applied to the research team, to continue the experiment himself. However, the fundamentally unstable nature of the strain led to his mental capacity peaking 19 days from infection and started to rapidly deteriorate by the 21st, manifesting alongside repeated seizures and a sudden destabilization of his mutations. With a poor prognosis, Swann's fears of being dumped in the Commonwealth were eventually realized as he was ejected onto the surface, having somehow retained the experiment logs.

After his expulsion and abandonment, Swann eventually made his way to Boston Common, an abandoned park in the downtown ruins, where he made his home in the groundskeeper shack. It was here that he finally lost his mind to his mutation, eventually creating armor from the swan boats of the pond and developing into a behemoth.

It was only after his arrival that the Common became a place not only to be avoided at all costs, but to be fundamentally feared. The bodies of victims who did not heed the warnings are strewn about the Common.

Daily schedule
Swan has a schedule which is uncommon for scripted characters. Around 1:00 AM to estimated 5:30 AM, he can actually be found roaming around the edge of the pond. The rest of the day he spends submerged in the water.

Effects of player's actions
Swan is a boss creature found at Swan's Pond, an outdoor location in the middle of the city. In the middle of the pond is a pile of debris made up of a white swan, a tire and a branch; this pile occasionally shifts in place. Should the Sole Survivor or their companion approach the mass, it will reveal itself with a roar, emerge from the water and start attacking. Damaging the pile may also cause Swan to emerge.
 * Swan's combat consists of four attacks: A devastating slam on the ground with his anchor, which deals massive damage and knocks the player character down, a charge attack where he slams the player character with his "boat shield," a ground stomp that deals tons of AoE damage and, like other super mutant behemoths, he's able to throw rocks from a distance, but this deals minor damage, depending on level.

Appearances
Edgar Swann appears only in Fallout 4.

Behind the scenes
His backstory seems to be inspired by the book Flowers for Algernon by Daniel Keyes, sharing many similarities with the main character Charlie Gordon.