Definitive 'primarily known for one song' band?

[Darsnan]

Sly Fox Lets Go All The Way:

 

[Kyriakos]

Imo this is another clear-cut example of a band primarily known for one song:

The singer also rocked outside music, in court hearings about whether music makes teen violent.

 

[Kyriakos]

If I had to choose one, I would go with this being the most famous by Primus:

 

[Darsnan]

Its Mosh Pit Monday, so its time to get a little Insane in the Brain!

 

[Kyriakos]

Its Mosh Pit Monday, so its time to get a little Insane in the Brain!

A classic and certainly their most (or even just "only") famous song.