Step 1. Activate Lost World
Step 2. Normal summon Souleating Oviraptor
Step 3. Using Souleating Oviraptor's effect, Send Giant Rex from the deck to the graveyard
Step 4. Using Lost World's effect, Special Summon an Egg token on the opponent's field
Step 5. Using Oviraptor's effect, target the egg token to be destroyed. This activates Lost World's effect, destroying Petiteranodon from the deck instead
Step 6. Using Petiteranodon's effect, special summon Dinowrestler Pankratops from the deck
Step 7. Activate Ultimate Conductor Tyranno's effect, banishing Petitranodon and Giant Rex to special summon itself
Step 8. Activate Giant Rex's effect, special summoning itself from the banish zone
Step 9. XYZ summon a rank 4 monster using Giant Rex and Oviraptor