In our movie[^] we had a scene where Scarless (me) has vegemite on his hand. For the purpose of the script it was soot but we used vegemite for no better reason than we could.
The mechanics of the scene were simple; my sidekick and I are in the forensic lab with the Professor and his sidekick. We shake hands.
'Scarless, Professor' (Professor and I shake hands).
'Scarless, Beaker' (Beaker and I shake hands).
'Professor, Festering Wound' (The Professor and Festering Wound shake hands).
'Festering Wound, Beaker' (Festering Wound and Beaker shake hands).
You, the audience, are supposed to have seen that I start the scene with vegemite on my hand, it's transferred to the Professors hand, thence to Festering Wounds and finally to Beaker.
We stole the idea shamelessly from this movie[^] which, it should come as no surprise whatsoever, I watched tonight. First time I've seen it in probably 20 years which doubtless explains why it was that I could not, for the life of me, remember the movie from which we'd stolen the scene.
The source movie does it rather better than we did but then again, we condensed a five minute segment into somewhat less than a minute. In the source the 'heroine' takes her chewing gum out of her mouth and sticks it under a table in a cafe (disgusting habit). Then we get to see that chewing gum do the rounds of at least a dozen sets of fingers before it returns to under the table.
Of course, as the gang leave the cafe she reaches under the table to retrieve the gum and..... but no, if you want to know the punchline see the movie! :-)