"That is one of his many practical jokes" is just a statement, neither an adjective nor a proverb, although the words many and practical are both adjectives.
many
A classic practical joke that you see a lot in television is the spring load snake in a peanut brittle can. They have had to update the cans with more modern labels to help keep this prank viable.
One, many, and practical are all adjectives
many
In his book - Complete Works of Charles Dickens (Illustrated). Dickens refers to many practical jokes of the time and often endorses them. It can be assumed from many of his writing that he did indeed have a sense of humour especially so when he wrote as Boz
The word "naught" has many meanings. When used as an adjective, it means that something is worthless. If it is used as a proverb it means "nothing" or "zero."
In the proverb "Too many cooks spoil the broth," the word "too" functions as a degree adverb. It modifies the adjective "many," indicating an excessive amount. This implies that having an overabundance of cooks leads to negative consequences, emphasizing the idea of excess.
100,000,000,000 jokes
Two.
A trap video on YouTube is a video that does not contain the content it claims to. Many of these are either practical jokes such as rickrolls or provide a link claiming to lead to the "real" video.
Simply as a result of there being so many jokes made up!
One can find joke about the causes and symptoms of IBS on sites like all jokes, heel that pain jokes, jokes forever, million jokes, jokes for life and many more.