Alpha-sapphire: From its mouth Gloom drips honey that smells absolutely horrible. Apparently, it loves the horrid stench. It sniffs the noxious fumes and then drools even more of its honey.Omega-ruby: Gloom releases a foul fragrance from the pistil of its flower. When faced with danger, the stench worsens. If this Pokémon is feeling calm and secure, it does not release its usual stinky aroma.Y: The honey it drools from its mouth smells so atrocious, it can curl noses more than a mile away.
Prof. Lotus' Notes: Gloom is based on the plant Rafflesia arnoldii a.k.a. the 'Stinking Corpse lily'. The plant got it's name because it smells like rotting flesh. Rafflesia is a parasite and it infects the plant host where a bud emerges. This has uncanny parallels to what happened to Oddish. The red discoloration of the leaves on it's head are also reminiscent to when plants are not getting nutrients, and this is because the parasite is leeching from the host Oddish. I suspect that the infected Oddish, Gloom, has two evolution lines because one is a scenario where the host cannot battle the infection, keeping it's susceptibility to spread the Parasite (Vileplume), and a line that was able to combat the Parasite and the healthy Oddish evolves to what it actually should have evolved into (Bellossom).
Gender Differences: Female Gloom have one large spot per bud, whilst males are covered in spots.