During Chapter 6 - Sanders residence - in Call of Cthulhu, you'll come across a Shambler, a monster that will crawl out from a picture under the same name. As the main character is unable to defend himself, it is impossible to fight the beast, which makes the whole battle extremely frustrating when you don't know what to do. In this chapter you will learn how to defeat the Shambler and unlock two achievements / trophies on the way.
As soon as you regain control of your character, turn 180 degrees and head towards the wall, all the time moving while crouching. Carefully enter the small room on the left - if the Shambler notices you (the music changes), quickly run for the wardrobe and hide inside.
Wait until Shambler goes away, exit the wardrobe and leave the room using the second passage and then get to the next room. If the enemy notices you during on the way, hide in the wardrobe and wait until it goes away.
Once the Shambler departs, leave the wardrobe and move to the corner of the room, to the display case standing between the furniture and the golden statue (the case is shown in the picture above). Break the glass with the interaction button and pick up the dagger. Since you just made a whole lot of noise, for safety reasons you should return to the wardrobe and wait for the enemy to move away once again.
Leave the wardrobe and locate the canvas from which the creature emerged. You now have to reach it quickly and interact with it. This will trigger a cut-scene during which the hero will cut the canvas with a dagger and (temporarily) exile the monster. After all is done, the room will return to normal and a short discussion with Cat will begin. For your heroic action you will receive two achievements - From Beyond and The Thing on the Doorstep.