Adding a pencil cup

The octopus model looks appealing so far, but it can be functional as well. The plan for this project was a cup holder, so it needs to have the shape changed so that things can be put inside it:

1. To start, temporarily turn off the subdivision surface modifier by locating the Subsurf modifier in the Modifiers tab and clicking the eye icon in it. Now, the simplified geometry is easier to work with:
   
2. Go to the Face Select mode (Ctrl + Tab) in the Edit Mode (Tab). Now, select the topmost face of the octopus:
   
3. Switch to Wireframe (Z) and the Front Ortho view (NumPad 1) and extrude (E) the top face into the body. Stop just a little above the red x axis line:
   

   Note

   It may be necessary to scale (S) the bottom of the cup a little so that it fits inside the body.

   After scaling the body will look this:

   
4. Now, the shape is generally right for a pencil holder. Turn the subdivision surface modifier back on by clicking on the eye icon in the Subsurf modifier in the Modifiers tab. You'll notice that the cup bottom is a bit too round to be a space-efficient cup:
   

   In the Edit Mode, edges can be marked with Crease to indicate to the Subsurf modifier that they should be sharpened.

5. With no points selected (A) in edge or point, select the mode (Ctrl + Tab), hold down Alt on the keyboard, and select and click on one of the edges around the top lip of the cup in order to select all the points in a loop around the top of the mug:
   
6. From the 3D View menu, navigate to Mesh | Edges | Edge Crease or press Ctrl + E on the keyboard. Move the mouse pointer up or down in order to increase or decrease the amount of crease applied to the edge until it looks good:
   
7. Hold Alt and select and click on one of the edges at the bottom of the cup to loop and select all the points around the bottom of the cup. It may help to switch to the Wireframe mode (Z) or temporarily turn off the Subsuf modifier:
   
8. This time, set the crease value by finding the Mean Crease setting in Properties (N). This setting can be any decimal number between 0.0 (off) and 1.0 (maximum). Click on the setting and enter 1, and then press Enter to set the value. Now, the bottom of the cup is flat:
   

This sort of edge creasing is a powerful way to control the Subsurf modifier. Note that the bottom of the cup is still circular even though the original mesh is an octagon. Subsuf smoothens out the other edges even if it's told to crease others. It's very smart!