When “沼” fills a head
Why it is in the set
推 covers the thing you support. 沼 covers what it does to your schedule. They are different states and the set keeps both, because a joke about being a fan and a joke about being unable to stop are not the same joke. 沼 is the one with the rueful edge.
What a head full of it looks like
Two in the morning, still reading. A hobby that has acquired equipment. Explaining to someone, at length, why the thing is more interesting than they think. A head led by 沼 is not unhappy. It has simply stopped trying to get out.
Words that use it
沼 (numa, a marsh), 沼地 (numachi, marshland), 泥沼 (doronuma, a quagmire — used of a dispute that will not end), 沼る (numaru, slang: to get stuck into something).
Kanji it turns up with
推 and 沼 together is the pairing the generator treats as one state. 沼 with 眠 (sleep) behind it explains why the sleep is not happening.
Where “沼” comes from
Water on the left (氵), 召 on the right for the sound. A body of still water: a marsh, a bog.
The slang sense is recent and vivid. To be 沼っている is to be stuck in an interest the way a foot is stuck in mud — the more you struggle the further in you go.
English reaches for “rabbit hole”, which is close but implies falling. 沼 implies sinking, slowly, with your eyes open.
A line you might get for “沼”
“In deep. Knows it. Not doing anything about it.”
Count the “沼” in your own headOthers in “Doing”
“沼” is filed under “Doing”. These are the rest of that group.
The 36 kanji
This is entirely a joke and has nothing to do with any real person.