Stop motion can use a wide range and combination of materials and not restricted to just the puppet humanoid or creature forms. Any real objects can be animated. Clay Animation is just another form of Stop Motion. There is a most unique animation method that possibly most of you are not familiar with, called, Strata-Cut Animation, the technique is attributed to, David Daniels. From what I read, he is suppose to have invented this animation method. As far as I know, David does not hide the technique of Strata-cut clay animation. At his website and at his Youtube video channel, he freely shares the knowledge. I think why David is open about Strata-Cut, is perhaps that this clay animation technique is very difficult and most people will not attempt it!? Maybe that is why he shares to keep strata-cut alive! His animation work first received public attention, way back in 1985 for a short called Buzz Box (14 minutes) ... it was a somewhat anarchistic, chaotic theme, like an acid trip with similarities to the mid-1960s counter-culture era of 'The Hippie' movement.
"Strata cut animation involves making 3-D controlled &sculpted pieces of clay shapes & forms in layers. It was invented by David Daniels. David lays out the clay in a four dimensional space to create the large block of clay. Then the clay is normally slid on popsicle sticks towards the camera as the front part is sliced off to reveal a new section of clay. Characters faces or images are animated in the 4-D space before the camera captures the movement. It's possibly the strangest way to animate, and has the look of oil on water during a breezy day."
If that is not understandable then maybe this simplified sketch might might help ....
In Geology, Strata means layers-slices of rocks, dirt, earth, etc ... so that seems like a good description of this animation technique. David Daniels' early work was on the ol' Pee Wee's Playhouse, then did work for Will Vinton Studios, and also did Strata-Cut animation for Michael Jackson's MoonWalker. David has done work (not just Strata-cut) at Bent Image Labs. Years ago David was one of the co-founders of that studio in Portland, Oregon (USA). Here is a montage of some of his past commercial work using the Strata-cut animation technique:
Journey Through A Melting Brain (The Stratacut of David Daniels) from Bent Image Lab on Vimeo.
In my quick research, it seems that Oskar Fischinger was an early experimenter of a similar Strata-Cut type animation method much earlier, in the 1920's. Doing a Google search gives us references to Fischinger. He was an abstract surreal artist-filmmaker and experimented with a ALL styles & methods of visual motion presentations ... graphics, stop motion, 2D, cut-out, including an early version of a simpler style of strata-cut. Daniels uses plasticene oil-wax colored clays, whereas Fischinger used Wax that was colored via random swirls & patterns within the wax block or log. Fischinger also devised a special wax slicing machine specifically for his Wax Animation work. I am guessing that Daniels' might have been inspired by Fischinger.
Another method that is possibly related to Strata-Cut Animation is, the Art & Craft of Clay Millefiori Cane Making using polymer clay which is used to make 'Clay Canes' by weaving the clay to make intricate designs. Clay Millefiori is not an animation method but a craft to produce pendants by slicing the cane to make multiple quantities of pendant shaped slices of the internal clay cane design. Each pendant is then baked hard. Here is an example Millefiori Cane Lion
For Strata-Cut Animation technique, one does not use polymer clay. The material of choice is, oil-wax based plasticenes which never hardens and is always pliable for sculpting. What is amazing about Daniels' Strata-Cut is, that he is able to weave the clay so that it creates intentional and planned movement from the process. Fischinger's work was more random & dependent on the accidental blending-patterns of the melted colored waxes. Daniels' Strata-Cut shows a somewhat control of motion of the internal clay weaving design. Stop motion in general requires patience but with Strata-cut, I cannot imagine the additional humongous patience this requires and especially, the mental pre-visionary abilities needed in planning the 'weaving of the clay' to create somewhat recognizable images. Results are crazy, nutty, and almost like a mind acid tripping psychedelic experience.
In 2005, David shortened his original 14 minutes long 1985 BUZZ BOX animation, and did a Remixed version. It is his old original work and some may not not have desire to watch it entirely. The remix is about 9 minutes. David Daniels later work is much more polished & refined, also done as short animation clips in which the audience would perhaps more likely view as a 'short' format package.
Today ... David Daniels seems to have a simple lifestyle doing his creative art at his home in Portand. He kind of reminds me of the late Bruce Bickford ... another creative artist doing much Clay Animation in a very experimental manner and having a hallucinogenic visual style.
David Daniels website and Youtube channel
UPDATE 2023: Interview with David Daniels ... for someone who does not animate, it gets a little technical
Wikipedia Strata-Cut Animation