Kind of in the theme of 塊魂, there's a yojijukugo with 4 鬼: 魑魅魍魎 (ちみもうりょう, chimimouryou, evil spirits of rivers and mountains)

I like words where one kanji is changed to make the meaning opposite (without changing the pronounciation)

名演 (great acting performance) -> 迷演 (baffling performance)

国道 (highway) -> 酷道 (road in terrible condition)

There are also some horrible ones like 毒女(独女) and 害人（外人）

Also 休館日 (museum holiday day) -> 休肝日 ("give your liver a rest day" - i.e. sober day)

It's not actually a pun (at least, AFAIK), but interestingly, 肛門 (anus) is an homophone of 後門 (back gate).

I have been wanting to learn Japanese but have been putting it off, you just convinced me that I have to get started learning it already. I love a good pun!