Still from Disney's 1974 "Duck Amuk" cartoon, in which after a long sci-fi tv marathon Donald dreams he is a member of the USS Enterprise's crew and is mistaken for science officer Spock, allowing hijinks to ensue. While not considered canon by the larger Star Trek fan community, it is widely considered one of the first crossovers between the franchises prior to Disney acquired the rights to the entire Star Trek franchise in 2012.
(Real still, btw. Supposedly it was to be part of an exhibition at EPCOT but seemingly canceled fairly early as there is virtually no information about it anywhere)