German compound nouns are often made fun of because of their length. To nonspeakers, they look monstrous and incomprehensible. But in reality, they are quite simple.
There's always at least two parts, with the first part determining the second and the second part being a noun.
Verkehrsunfall: accident in traffic
Nasenspray: spray for nose
Klimaleugner: denier of climate (i.e. climate change)
Then there's recursion: A compound may be used as the first part of another compound.
Verkehrsunfallstatistik: statistic about accidents in traffic
Nasenspraysucht: addiction to spray for nose
Klimaleugnerthese: proposition by denier of climate
These compounds may be well-established, such as Verkehrsunfallstatistik, they may be occasional, such as Nasenspraysucht, or they can be created ad hoc, such as Klimaleugnerthese.
As the literal translations indicate, these compounds are quite easily understood if read from right to left. However, when reading quickly, proper segmentation (at least for long or rare compounds) is sometimes a problem even for native speakers, which is why spellings with a hyphen, such as Nasenspray-Sucht, are becoming more popular.
The problem with
clownenschadenmitbananaundsafeleiderkaputt
is that it does not follow the rules for compound nouns: There's a prepositional phrase (mit Banane), a conjunction (und), an adverb (leider) and an adjective (kaputt) all mushed together, without any nouns that could serve as second part.