Kitchen sink conlang
A kitchen sink conlang is a conlang that has "everything including the kitchen sink", i.e. a pejorative term for a conlang of unrealistic phonological and/or grammatical complexity. While natlangs can be quite complex and a good naturalistic artlang reflects this, a kitchen sink conlang involves excessive complication without adding more depth.
No single feature can turn a conlang into a kitchen sink - what is called for is a combination of several perceivedly unusual features, or even ordinary features that do not "work together".