Subject's deformities are growing at an alarming rate. All facial features appear to have been swallowed up inside a mass of crusty flesh and fragments of growing bone are protruding out the subjects body. The mixture in the tonic was meant to dilute the effects of the substance, however they seem to be as horrific as before, different, but horrific nonetheless. I suspect soon the other subjects exposed to the tonic will swell as this one has and the labs in the house will be put at risk should the subjects size expand to the point of ...explosion. I will recommend the subjects be moved to the lower caverns where they will pose no danger.
Growth is a deformed human whose exposure to some form of Marrow has swelled their body up to the point of being so volatile that a single hard smack could cause them to explode and spill out the noxious gasses and fluids of their innards.
They quickly seek out any noise they hear in an attempt to destroy themselves at the hands of whatever creature has wondered into the spot they dwell, presumably to end the pain of existing as the hideous and bulbous creatures they've become.
The explosion which ignites from contacting the Growth is large enough that striking the enemy with one of the shorter weapons in the game will still leave the player in range of the blast and cause damage. A well timed fireball will stop them dead in their tracks but their quickness means any hesitation will be long enough for the Growth to get close; listening to the sounds of one approaching is key to reacting in time.
The Damage the Growth does is considerable, some of the highest in the game, but don't fret, along with the usual health and weapon upgrades Marrow's world also contains two earrings which cut the damage done by enemies greatly. Finding these are no straightforward deed however, unlike fairly common health upgrades you won't simply stumble upon them.
The odd statue of the basement in the Stuland Manor hides a secret
Other key items, like weapons and medallions are also tricky items to find, some requiring a careful memory of the many environments in the game and an observant eye of the subtle clues that will come your way.
Marrow OST - Decayed Madness