Here is how Princess Yuna tamed the I-Rex in Genesis World.
Later that night, All the visitors evacuate from the island.
Princess Yuna: The island has been evacuated and the Piranhaconda didn't follow anyone or anypony.
Princess Skyla: But what're we going to do about the Piranhaconda?
Twilight Sparkle (Human): It was going to hurt everyone and everypony.
Sunburst (Human): Even the Journals will be in Bill Cipher's hand right about now.
Prince Edmond: There must be someway we can do.
Princess Yuna: (looked at Journal 1) We just have to think of something.
Lucas: And fast.
Penny Peterson: Now what?
Gosalyn Mallard: Don't ask me, Yuna's our leader.
Fievel Mousekewitz: Let it go, Gosalyn.
Princess Yuna: There's always a way.
Mirage the Illusionist (Human): But what?
They kept on working on a plan to save Genesis Park.
Then, Yuna came up a plan. The plan is to find Dawn, And take down the Piranhaconda.
Princess Yuna: Alright, Gang. You all know the plan.
Snowdrop: Okay, Yuna.
Princess Sharon: I'm with you, Yuna.
Princess Yuna: Thanks, Sharon.
Princess Solarna: Same goes for me, Baby sister.
Twilight Sparkle (Human): We all are.
Sunset Shimmer (Human): Without a doubt.
Dewy: Let's do this!
Later, Flurry Heart, Skyla and the Royal Crusaders set the cameras on the four Velociraptors, Smilodons, Dire Wolves, Titanoboa and the T-Rex. The hunt is on, Yuna was on her Motorscooter and the Predators followed Yuna.
Princess Yuna: Time to save Genesis World!
And the search party begins once again, They have to pick up the trail for Dawn.
In the jungle, Yuna spotted something as the Journals begins to glow.
Princess Yuna: I think they found something.
Just then, Dawn came from her camouflage.
Snowdrop: What was that?!
Sunbeam: It's Dawn!
Bart Simpson: The I-Rex herself!
Dawn was about to devour when Yuna came forward.
Dawn: (growls and communicates with the Raptors)
Douglas: (growls and communicates)
Donna: (growls and communicates)
Princess Yuna: Those raptors are communicating with Dawn.
Princess Yuna: Don't you all remember? She's part raptor!
Dawn: (staring at Yuna)
Yuna stood up to Dawn and started taming her, She looked are her straight into the eyes.
Princess Yuna: Dawn. Easy, Girl.
Princess Yuna: I won't hurt you, We're friends. The Piranhaconda is not a friend.
Dawn: (begins to understand Yuna)
Suddenly, The Piranhaconda is coming up behind Flurry Heart.
Grenda: FLURRY HEART! BEHIND YOU!
Princess Flurry Heart: (looks behind)
Skyla and the Royal Crusaders: FLURRY HEART!
As she screamed, Dawn snatched Flurry Heart away with her claw.
Pirahnaconda: (missed Flurry Heart and slithered away)
Dawn: (shows herself from her camouflage)
Princess Flurry Heart: It's okay. I'm alright.
Dawn: (makes a gentle growl)
Dipper Pines: I've never seen her up close before.
Phineas Flynn: Me neither, Dipper.
The Royal Crusaders: Whoa!
Bart Simpson: Ay Camabra!!!
Princess Yuna: (pets her) Good girl, Dawn.
Yuna knew that she was able to tame the Indominus Rex, She led her straight to the park.