The cancelled Flaming Carrot episode?
 

When thinking back, I did remember seeing something float around that there was going to be a Flaming Carrot episode. Looking into it, I did find one article (that I'm pretty sure came out way after I heard about it) confirming that it was an idea floating around:
https://www.comicsbeat.com/sdcc17-tm...series-finale/

The odd thing here is that Nickelodeon allegedly rejected the idea because "nobody wants to see a guy with a carrot for a head", which is a bit odd because this is the show with the cat made of ice cream, a giant walking pizza and a chicken with an oversized brain, so I'm not sure what the problem would have been with the carrot guy.

I guess Nickelodeon was scared that kids think vegetables are gross.

These three examples are concepts created by the staff and fit very well with the fun vibe they were going for, weird as they may have been.

Flaming Carrot? I never got it. Very strange character created by a Boomer for a niche indie comic. Kids probably would have sensed that he was lame.

It was a weird character created in a time full of weird characters, like the Turtles or Cerebus.

It's weird IDW has never reprinted the 4-issue Mirage Flaming Carrot crossover. I wonder if they can't get the rights.