Vampire of the Haunted House!
Mondo and Rokuna are trapped inside a haunted house, hunted by the vampiric creature Collection has become.
Aired 21/08/2000EP 33 - Vampire of the Haunted House!

2000
Mon Colle Knights
Scientist Ichiroubei Hiiragi discovers the existence of Six Gates, an otherdimensional world full of monsters and powerful hidden treasures known as Mon Mon Items. Ichiroubei embarks with his daughter, Rokuna, and her classmate, Mondo. However, they're foiled at every turn by Count Collection and his assistants, who want the Mon Mon Items in order to conquer both worlds. Becoming the heroes known as Mon Colle Knights, Mondo and Rokuna join forces with the monsters, striking back against Count Collection while searching for the Mon Mon Items in the name of friendship between their worlds.
(Source: Crunchyroll)