The latest Shen Gong Wu to activate is the Rio Reverso, which has the ability to revert anything back to its original state. Thanks to Wuya's behind-the-scenes manipulations, it ends up in Jack Spicer's hands, who after playing with it a bit, discovers that oil used to be dinosaurs and intends to use this knowledge to create his own army of dinos. Unfortunately, Wuya intends to claim the Shen Gong Wu for herself, and then when Chase Yong gets involved, it results in Raimundo taking on a super-smart T.Rex on a very surprising battleground.
Tropes:
- Big Eater: By Clay's own admission, he eats so much that Master Fung can barely keep food in the temple.
- Car Fu: Wuya uses the Ruby Of Ramses to hurl Jack's car into Raimundo's face, causing it to explode.
- Chronic Backstabbing Disorder: Prevalent throughout the episode with the Heylin — Omi lampshades it best: "Aaaah, so much criss-crossingnote ! This proves there is truly No Honor Among Thieves!"
- Wuya goes behind Chase's back to get the Rio Reverso and uses Jack as an attack dummy.
- Jack gets back at Wuya by putting a tracer on the Rio Reverso (before she had stolen it from him) and teams up with Chase to retrieve it.
- Chase uses the Eagle Scope to enhance the T.Rex's IQ and leaves both Jack and Wuya at the dinosaur's mercy,
- Dinosaurs Are Dragons: Discussed — after Clay argues that Dojo's "practically one of [those dinosaurs]," Dojo gets offended and claims that'd be like him saying humans are practically monkeys. However, the T.Rex does devour a fireball and spit it back out without any noticeable damage.Clay: Dojo you're practically one of them critters! Have any ideas?!
Dojo: I beg your pardon!! That's like me saying you're practically a monkey! She's prehistoric, and that's offensive to dragons! Just because she speaks with a British accent doesn't make her smart! We breathe fire, fly, and chew with our mouths closed! - Evil Brit: After Chase enhances her IQ with the Eagle Scope, the T.Rex starts speaking with a British accent.
- Evil Is Not a Toy: Wuya brings an adult dinosaur back to life. In her weakened state (and with the Shen Gong Wu not working on it), it immediately smacks her (and Jack) away with its tail.
- Grievous Harm with a Body: Wuya using the Ruby of Ramses (twice) on Jack to put a serious smackdown on the Xiaolin monks; Omi actually ends up relieved when it turns out to be this rather than Spicer taking a sudden level in badass.
- Hidden Depths: Raimundo proves to be very knowledgeable and skilled when it comes to chess — this greatly surprises his teammates and Dojo, with Kimiko outright stating "I had no idea Raimundo could do anything using his head!"
- Mass "Oh, Crap!": Xiaolin Monks' shared reaction when T.Rex simply swallows the Arrow Sparrow and then spits it back at them.
- No-Sell: All of the Shen Gong Wu end up bouncing off the T.Rex — it ultimately takes Raimundo outsmarting the dinosaur to finally defeat it.
- "Oh, Crap!" Smile: Wuya grins sheepishly when her previously effective tactic of using Jack for Grievous Harm with a Body doesn't even phase T.Rex, earning her only its Death Glare.
- Once an Episode: The showdown in this episode is between Raimundo (who uses the Ruby of Ramses) and the T.Rex (who uses the Changing Chopsticks), with the latter making their showdown a game of "Jurassic Chess," with the first to place their opponent in checkmates wins — Raimundo ends up winning.
- Puppy-Dog Eyes: Jack does this as he demands Wuya to give the Rio Reverso back.
- She's a Man in Japan: In original dub, T.Rex is very clearly female (in possible reference to Jurassic Park, where all dinos were such). In Polish dub, it is voiced by male actor instead.
- Smart People Play Chess: T.Rex and Raimundo.
- Take a Third Option: After defeating the Heylin, the monks are wondering what to do about the T.Rex that Wuya brought back to life from the oil — obviously they can't do something like turn her back into oil or set her free. Omi ultimately suggests taking the T.Rex back to the temple with them — the others aren't too sure about this, but Omi elaborates on his idea by shrinking the T.Rex down to where she's small enough to fit in the palms of Omi's hands. They end doing to the rest of the dinosaurs as well and ultimately keep them as pets at the temple.
- The Unreveal: Played for Laughs. Jack Spicer attempts to use the Rio Reverso on a chicken to figure out "which came first". Unfortunately, the chicken ends up cycling through being a chicken and an egg with Jack realizing that some questions will remain unanswered.
- Uplifted Animal: Chase Young uses the Eagle Scope to make the T.Rex Wuya brought back to life intelligent.
- Wicked Cultured: The T.Rex speaks in a sophisticated British accent and plays chess.
- Worf Effect: Wuya's strategy of using Jack to bodily harm the flesh-and-blood monks hardly phases a T.Rex whose skull and jaw, historically speaking, are as hard as diamonds.
