As you venture around Neopia you may get a Battledome Challenger, here is a list of all the ones that currently work

Opponent	Details
	Mummy HP 42 visit here
	Punchbag Bob HP 0 Automatic - good for testing weapons
	Punchbag Sid HP 150 (Bob's evil twin) he may randomly appear whilst fighting Bob BUT unlike Bob, he hurts you
	The Brain Tree HP 91 Do one of his quests
	Pant Devil HP 21 Random Event
	Jelly Chia HP 125 visit this Gallery of Evil page
	Count Von Roo HP 90 Random Event
	Lava Ghoul HP 120 Random Event
	Mutated Chia HP 40 Random Event
	Flaming Meerca HP 40 Automatic
	Shadow Usul HP 175 Random Event
	Tiki Tack Man HP 63 Visit the Tiki Tack Shop
	Balthazar HP 320 Random Event at the Haunted Woods, fight him and lose to receive this avatar
	Edna HP 80 Complete one of her quests, she comes out for battling only between 12am and 1am NST
	Grarrg HP 100 Get him at the Tyrannian Town Hall
	Chiazilla HP 500 Random Event refreshing here
	Spider Grundo HP 175 At this Gallery of Evil Page
	Snowager HP 650 Get Blasted by Snowager
	Harry the Mutant Moehog HP 35 Automatic
	Sabre-X HP 79 Random Event around the Tyrannian Plateau
	Kauvara HP 70 See her Neopedia entry
	The Esophagor HP 49 Complete one of his quests, not as a part of The Brain Tree Quests
	Cave Chia HP 58 Random Event here and refresh (a lot)
	Snow Faerie HP 105 Complete one of her quests
	Ryshu the Nimmo HP 250 Visit the Mystery Island Training School Courses page
	Robo Grarrl HP 150 Automatic
	Koi Warrior HP 62 Random Event when refreshing here
	Space Faerie HP 450 Reedem a Rare Item Code here
	Magnus the Torch HP 85 Go here (you may need to refresh)
	Clown Chia HP 10 Automatic
	Highland Chia HP 58 Automatic
	Meuka HP 60 Get Sneezles or Neoflu and take a look at your pets Quick Ref.
	Commander Garoo HP 120 Random Event here
	>Ghost Lupe HP 32 Go to 131 soup alley
	Kasuki Lu HP 38 Have the card Kasuki Lu and view it (just click on it)
	Tekkitu the Witch Doctor HP 120 Go on the Tiki Tours
	Zafara Rogue HP 39 Visit the Deep Catacombs and refresh
	Vira HP 80 Random Event
	Tax Beast HP 85 Random Event - if he finds you he will take 10% of your np on hand
	Sidney HP 84 Win a Level 3 or above prize with one of the Deserted Fairground Scratchcards
	Advisor Broo HP 130 Random Event whilst playing Dice-a-roo
	Plumbeard HP 260 Visit him in his room at the Swashbucklers Academy
	Black Pteri HP 89 Random Event
	Meerca Henchmen HP 150 Visit the Desert Trapdoor and refresh (a lot) (if you get an old book, ignore it, its from an old mystery.)
	Giant Ghostkerchief HP 250 Visit this news page - (from Halloween 03).
	Boochi HP 15 Random Event - Your pet will be turned into a Baby
	Evil Sloth Clone HP 85 Visit Kreludor
	Snow Beast HP 300 Random event Advent Calendar ( may not work whilst the advent is out of use, try in December)
	Giant Hungry Malevolent Chomby HP 350 Random Event Here
	Turmaculus HP 225 Wake up turmy and have him eat your petpet
	Mootix Warrior HP 375 Automatic
	Down for Maintenance Pteri HP 75 Random Event
	Lab Ray Scientist HP 185 Random Event within the Secret Lab - You need to have a complete lab map to get this one
	Kastraliss HP 400 Type Kastraliss in the search bar on the left and refresh the page that comes up until you get the challenger
	Inflatable Balthazar HP 1 Automatic
	Slug Monster HP 500 Have Slug Flakes in your inventory and visit here you will need to click the central section and get the go away sea slug ~ thanks to big_jmwp
	Quiggle War Lord HP 69 Have your Quiggle do a battle (I did a 1 player against Inflatable Balthazar, won, pressed next and the event appeared)
	The Drenched HP 600 refresh here
	Qasalan Mummy HP 550 refresh here
	Greedy Kadoatie HP 125 Random Event - You will receive the challenger when you lose 5000np in the Mutant Kad event
	Mr Chuckles HP 10 Refresh at the Coconut Shy
	Eyrieki HP 25 Visit the Lost Desert Temple and enter one of the doors