Welcome, today we'll be making this:
I found a photoshop tutorial and thought the outcome was pretty cool so I tried it with PDN. The outcome was useful (IMO) so I thought I'd post a tutorial on it. Photoshop tutorial.
You will need the custom brushes plugin as well as a blood splatter type of brush (if you run a search on this site you'll come up with a lot). I used this brush pack.
1st step: Start off with a canvas size of about 300/300. Get your line tool and draw a black, curved line in the center of your canvas at about 30 pixels. We'll call this layer line A:
2nd step: Create a new layer and name it line B. Draw another line at the bottom of line A on this layer with a different color (as its easier to see). Draw this starting at the right end point of line A and finishing at the left side of your tentacle in a smooth arch. Right click to create a smooth curve. This will make it seem like line A is tempering out like a tentacle:
3rd step: Delete everything on the left side of line B on line A. Delete the line B layer. Now we have the basic outline for our tentacle:
4th step: Duplicate your line A layer and invert colors (Adjustments/invert colors or CRTL+Shift+I). Get your Magic Wand tool and at 0% tolerance Select the transparent part of this layer and then invert selection (Edit/Invert selection or CRTL+I). Run a Gaussian Blur with a radius of 18. Merge this layer on to line A and you should have something like this:
5th step: Duplicate the line A layer and set the top layer to multiply. Merge this layer down. Now add a new layer and name this layer Blood. Set your primary color to a dark red (used hex #5B0000). Go to custom brushes and randomly add blood splatters across the canvas:
6th step: On line A get your Magic Wand with a tolerance of 60% and select the transparent background. With this still selected go to your Blood layer and hit delete. Go back to your line A layer and run a gaussion blur of 2%. Duplicate this layer then merge it down. Double click on your Blood layer or go to propertys and set the blending mode to Color Burn (Glow gives a good affect as well and you can always just leave it as is):
7th step: Flatten your image. Select the transparent background (with your magic wand at 0%) and once again invert your selection (CRTL+I) and feather it (Effects/Selection/Feather Selection) at a radius of 3. Wah-lah, now your finished. You can use lighting or anything else you like to give it a 3d look but this is as far as I went with it. Although I prefer mine to be a little thinner so I usually stretch 'em vertically and make 'em smaller. Heres my final result:
Used this technique to make a sloppy signature: