It is a method to make some puppets and replace them one frame at a time. It is also called replacement animation. If you repeat the same transformation over and over again, make puppets for one transformation and use them repeatedly.
Make 3 puppets that running 2 puppsets and sitting.
It is that I shooting with replacement animation.
It is a sample animation.
There is also a method of shooting by replacing a part such as a face.
Now we can make hundreds or thousands of parts using 3D printers and can move more precisely.