On YouTube in a video showing off the arcade game Turtles in Time, one of the enemies was a monster similar in appearance to the Xenomorphs from the Alien films. Has such a character ever appeared in any of the comics or TV shows?
It's a Pizza Monster, and it does appear elsewhere. They appear in a 1987 episode of the TV series, The Case of the Killer Pizzas:
The plot of this episode hints ever so slightly at Alien: Pizza Monster eggs look like meatballs and they were put on pizza to try to trick the turtles. If the turtles had eaten the "meatball pizza" (instead of it being put in the microwave and hatching without being eaten), I think we all know what would happen...
Another cool thing to note is that Toy Manufacturer NECA made a yellow Sewer Mutation Warrior Alien as a reference to this.