"Do not try to bend the spoon. That's impossible. Instead, only try to realize the truth." "What truth?" "Ложки нет." "Say what?"
Because when you have "нет" (which is to say, trying to express the absence of something), the object of the phrase (the thing of which there is nothing) must be in the genitive. Basically, you are saying that "there is none OF a spoon", or "there are none OF spoons" (tortured when put literally in English, of course, but that's the sense in Russian -- perhaps a slightly more idiomatic way would be "there is a lack of a spoon" / "there is a lack of spoons").
So while ложка / ложки are the singular / plural for spoon in the nominative, the genitive has ложки / ложек for its singular and plural.
(Most feminine nouns have the plural nominative the same as the singular genitive. Why? shrug that's just the way it is.)
So: "There is no spoon." = "Ложки нет." "There are no spoons." = "Ложек нет."
(But: "There is a spoon." = "Ложка есть." "There are spoons." = "Ложки есть." ...because a thing which is actually present, is expressed in the nominative.)
TL/DR: sigh. Russian.