Splinter tells the turtles about their early days of surviving in the city as mutants and evading the Kraang.
Written by the Turtles and Splinter's co-creator, Kevin Eastman.
- Character Development: Splinter goes from calling the boys "Turtle creature" to protecting them as his own sons.
- Flashback with the Other Darrin: Despite the episode taking place well before the beginning of the series, let alone the events that led to Leo's throat injury, he is voiced by Seth Green as a child instead of Jason Biggs or Dominic Catrambone.
- Hidden Depths: Splinter wanted to be an artist when he was younger. Hence why he probably named his sons after artists, especially since he mentions the Renaissance being his favorite period of the arts.
- Irony: Splinter gives Donnie his bo staff because of his thoughtful soul and peaceful heart, only for Donnie to complain about receiving a stick. Also Raph the turtle who's "got the most attitude on the team" is the only one to thank Splinter.
- Origins Episode: This episode reveals how Splinter and the Turtles came to live in the sewers as well as why Splinter gave the Turtles their respective weapons.
- Mythology Gag:
- The episode's title, "Lone Rat and Cubs", is not the first Shout-Out to the manga in the franchise. A one-off episode in the 2003 series was titled "Lone Raph and Cub".
- Splinter and the Turtles' first hideout is an empty water tower on a rooftop, much like the water tower the Turtles temporarily lived in during the City At War arc in the original Mirage comic.
- Papa Wolf: Splinter when protecting the turtles and fighting the Kraang. Special mention goes to Raph getting run over by Splinter's cart and receiving the crack on his plastron making Splinter go nuts against the Kraang.
- Revision: The episode expands upon Splinter's time with the Turtles after he and them were mutated.
- Series Continuity Error: This episode shows Splinter giving the turtles each of their weapons and they have their masks. Requiem shows Leo receiving a sword from Splinter but he's not wearing his mask and the other turtles weren't in the flashback. Of course that might simply be how Leo remembered it.
- Shout-Out: The title "Lone Rat and Cubs" is one to Lone Wolf and Cub.
- When the Kraang find Splinter's second hideout, the lead Kraang tells the others to "EX-TER-MIN-ATE! EX-TER-MIN-ATE!".
- Whole Episode Flashback: Literally, the entire episode is set in two different past periods, when the turtles were kids and when they were baby mutants, leaving the present day characters completely gone.
