After defeating the 12 rare Zodiac Monsters (the most difficult and time consuming task) that appear after beating the game, a special cutscene will play where six female characters (Holly, Colt, Viola, Minta, Crysta, and Miss Sapphire) confront the player, Errick and Cleo. Holly and Colt tell them they gathered everyone together to celebrate the defeat of the Zodiac Monsters, but their extremely suggestive praises of the player and anticipations of celebrating "tonight" (with Viola commenting she wants to see what makes him "tick") anger Cleo who feels that she is not being given proper credit and suspects something is up. She tries to save him from the encounter, but Viola attacks her and she appears to fall unconscious before he is "captured" and taken away by the six women. What then occurs is a fade-to-black followed by the Rest theme, and the sound of two owl hoots. The scene then cuts to the following morning, where Errick remarks that he is jealous of the player and Cleo returns demanding to know what the player did last night as Holly and Colt giggle. She angrily denies him supper for a month, while Holly comments she will give him some of hers behind Cleo's back.

This cutscene heavily implies that the player partook in a harem orgy, with Colt in particular implying that the player took her virginity. Monster Rancher DS was rated E for Everyone by the Entertainment Software Ratings Board (ESRB), but their rating still points out the game features "Mild Suggestive Themes". It's unknown if this warning was added to refer to this scene, or if the game's publisher intentionally left out this scene when submitting content for review.