Dirty Bubble Challenge

Dirty Bubble Challenge
Character Used
Health
Available Rooms
Treasure Rooms	yes
Shops	yes
Goal
Unlocks
Petrified Gel

Dirty Bubble Challenge is a challenge added with the initial release of Fiend Folio. In this challenge, the player starts as Isaac with no items, and every enemy projectile is replaced with a Bubble of a random size. The goal is to defeat Mom's Heart or It Lives.

• Flaming projectiles produced by enemies such as Fried or Mr. Flare, or explosive projectiles produced by enemies such as Gurgle will turn into Explosive Bubbles.
• Homing projectiles are replaced with Fly Bubbles.

Difficulty

• This challenge shows its true potential when you encounter a room with a lot of projectile-based enemies. Monsters like Beeter or Dung can cause some serious problems.
• The bubbles move slowly and do not always aim towards the player, but they block Isaac's tears, meaning it's much harder to hit enemies which, in turn, can make the player become overwhelmed with the amount of bubbles created.
• Bosses like Monstro or Buck can become much more difficult, while Widow or Little Horn are almost unchanged.

Strategies

• The player should focus on item effects that pierce through enemies, such as Cupid's Arrow or Technology, since they will greatly help when dealing with the amount of bubbles.
• Try to focus on killing enemies that shoot projectiles first before any other monsters to avoid being quickly flooded with bubbles.
• Familiars designed to block projectiles, like Dry Baby, won't help much in this challenge as bubbles are treated like enemies, not bullets. Instead, take damage-dealing orbitals like Cube of Meat.

Unlockable Achievements

• 

  Petrified Gel — Complete Dirty Bubble Challenge.

Trivia

• Dirty Bubble Challenge is a reference to a moment in the Spongebob Squarepants episode "Have you Seen This Snail?", where Spongebob gets a package containing the Mermaid Man and Barnacle Boy paddle ball set, which includes a sheet which details the Dirty Bubble challenge where the paddle ball must be hit 29,998,559,671,349 times.