Sam when he holds the Ring for 5 seconds

This is a "I'm something of a scientist myself" meme, and also a Lord of the Rings meme. The "I'm something of a scientist myself" meme is usually used to indicate that the person pretentiously categorizes themselves as something that they do not really qualify for because they did something that is sort of like the thing that the person that they are categorizing themselves as does. This is (if it wasn't obvious) an insult.

In this instance, since Sam carried the ring for a few seconds, he is considering himself to be a ringbearer.

I didn't find this meme to be particularly funny - but perhaps it is because I don't think that Sam ever pretended to be more than he was.