If Masters Tai and Chi were still around when Yin and Yang were babies, that means their battle with Eradicus wasn't that long ago.
It appears that Eradicus paid for Ella Mental to take tuba lessons off-screen (and no doubt, against her will since she didn't want to play it.)
At the end of the episode, it appears that Ultimoose is beginning to start a dating relationship with Coop's Mother.
At the end of the episode, the site of the old Night Master's lair has been turned into a dump and Ultimoose has set up a shop there selling inflatable balloons.
Running gags in this episode: 1. The parents of the Woo Foo Army keep telling their children to not fight at all, before relenting and allowing them to fight Eradicus' minions. 2. Lena is forced to keep telling the Woo Foo Army to retreat whenever things get too dangerous for them. 3. Yang's sword keeps glowing and keeps trying to inform Yang of information currently unknown to him.
Finale of Season 2 as Yin and Yang are 'reunited' with their father Master Yo, the Woo Foo Army goes off to protect their own homes, Eradicus has been destroyed again, and Eradicus' minions are defeated. Although this episode is intended to serve as the series finale, the door has been left open for a possible Season 3 and/or spin-off series due to still unanswered questions about some of the characters and the introduction of a new villain named Ferocitus.
New Move Debuts: Eradicus' Woo Foo Aura Drain is a medium sized black sphere with red lines in it that completely drains someone of their life-force, energy, and can eventually cause death if not reversed; it can only be cured by a Woo Foo Transfusion. Master Yo/Yang/Yin's Woo Foo Transfusion allows family members to transfer a part of their energy and life-force to another family member in order to cure a Woo Foo Aura Drain. Yang's un-named sword scent move allows his sword to glow with energy and seek out any of Yang's fellow relatives, and can find other people, but the move is a bit unreliable as it tends to pick out anyone who has traces of Yin's and/or Yang's Woo Foo on them.
Lena finally uses Woo Foo powers for the first time in the series, using the Paws of Power move and a Flaming sword.
Continuity Error: In Eradicus's memory of when he terrorized the world in the past, he had the appearance he had in the present, but shouldn't he have had the appearance from Doomed To Repeat It?
Apparently, Eradicus has a thing for polka music, specifically the accordion as people were terrified by the music in his old days.
It is revealed that Master Yo is Yin and Yang's father; his memory of them had previously been erased by Masters Ti and Chai so that he could train them without bias or fear. Masters Ti and Chai were forced to look after Yin and Yang after Master Yo's memory was erased; however, the identity of their mother remains unknown.
Apparently, one of Master Yo's old girlfriends lives in Redneckistan.
Running gags in this episode: 1. Ella Mental keeps brainwashing Dave's family into insulting him and degrading his already low self-esteem. 2. Indestructo-Bob talks about what he has been doing and is doing by referring to himself in the third person by calling himself Bob. 3. All the Redneckistanians in Redneckistan talking like hicks (until they spit out all of the possums that had lived in their mouths.)
It's learned in this episode that in addition to being able to read minds, Ella Mental can also control other creature's minds, and control many minds at once. Of course, the more minds Ella Mental tries to control, the harder it is for her to concentrate on keeping those minds under control.
It's revealed in this episode that Dave has been infatuated with a walking, talking, tree girl named Willow ever since he was a sapling. And based on the affection Willow gives Dave after Dave pounds Ella Mental with his powers, Willow becomes Dave's girlfriend.
Dave briefly breaks the 4th Wall in this episode when he mentions how even though he has control of trees that can already walk, talk, and move around; nobody ever bothers to explain why some trees can walk, talk, and move around.
It's learned in this episode that Master Yo has been transmitting his image and voice through a magical sun reflector from a Magical Spa Retreat, which is where Master Yo foo-portated to take a vacation after Eradicus blasted him. Ironically enough, Master Yo gets captured by Eradicus at the end of this episode.
Indestructo-Bob briefly becomes the King of Redneckistan until Jobeaux beats him. Jobeaux then ascends from being a Prince to being the King of Redneckistan; and Jobeaux decides that since he thinks people in Redneckistan don't HAVE to act like Rednecks anymore, Redneckistan is officially re-named, Stan.
It's learned in this episode that the name of Jobeaux's girlfriend, is Annie. And up until this episode, everyone in Redneckistan had a possum living in their mouth's.
It seems odd that Eradicus still has the previous Night Master's army after he returned it to the previous Night Master's yard sale (unless Eradicus wasn't able to sell it back because of the damage the army encountered in Shadowcluck.)