Phantasmagorie (1908) Emilie Cohl

One action morphs into another one or disappears gradually preparing the space for the other to take place. Characters transform into objects in order to keep continuous relationship between them ( for instance one character, the champagne bottle, takes the clown captive then turns into a blossoming flower setting him free and so on),

So you become aware of the good continuity kept throughout the animation.

Phantasmagorie (Fantasmagorie) is considered to be the first fully animated film ever made.