Binding of Isaac: Rebirth Wiki
Cat   Got   Your   Tongue
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Challenge Number
Available Rooms
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Unlock Method

Cat Got Your Tongue Become Guppy

Cat Got Your Tongue is challenge #8. Isaac starts this challenge with Guppy's Head Guppy's Head, Guppy's Tail Guppy's Tail, and Guppy's Hair Ball Guppy's Hair Ball, as well as three Soul Heart Soul Hearts and three Black Heart Black Hearts, as well as his usual three Red Heart containers. Isaac is also blindfolded. This challenge is unlocked by transforming into Guppy Guppy. The goal is to defeat Mom Mom.


  • As a result of the blindfolded status, tears cannot be used, and Isaac must rely heavily on the erratic movement of Guppy's Hair Ball to do damage.


  • Because Isaac starts with 3 Guppy items, he begins the challenge as Guppy Guppy, which grants flight (a good way of avoiding damage) and generates Blue Flies when dealing damage with familiars or a co-op baby.
  • Guppy's Hair Ball also creates blue flies when dealing damage which is a feature unique to challenges where Isaac is blindfolded, making it considerably stronger than normal.
  • Due to this challenge requiring the player to get up close and personal to enemies, ones that explode upon defeat can pose considerable risk to the player. It's recommended to use Guppy's Head to generate flies to fight the explosive enemies for you.
  • Guppy's Hair Ball is very difficult to control. It would be wise to spend the first few attempts at the challenge by practicing with it before a real attempt at completing the challenge is made.
    • Items that increase movement speed can make Guppy's Hair Ball somewhat easier to use. The extra speed will allow for more precise control while also increasing the range indirectly at which the Hair Ball can safely be swung.
  • Buying 9 Volt 9 Volt from a Shop or finding the Added in Afterbirth †Fish Tail Fish Tail can allow more Blue Flies to be spawned by Guppy's Head.
  • BFFS! BFFS! is a noteworthy item due to its effects on Guppy's Hair Ball.
  • Orbitals, such as Cube of Meat Cube of Meat and Sacrificial Dagger Sacrificial Dagger, can be more effective than Guppy's Hair Ball at blocking and dealing damage.
  • Hive Mind Hive Mind greatly increases the damage of Blue Flies.
  • Added in AfterbirthIncubus Incubus is a notable item for easing up the challenge, essentially turning it into a slightly harder Lilith run.
  • Red Candle Red Candle or The Candle The Candle can be useful alternatives to Guppy's Head, depending on the situation.
  • Bob's Brain Bob's Brain, while dangerous, can serve as a reliable alternative to bombs.
  • Added in AfterbirthSpear of Destiny Spear of Destiny can trivialize the challenge by providing an easy-to-use alternative for dealing damage.



  • "Cat got your tongue" is an idiom for when people are speechless.
  • Aside from the obvious change in language, the Korean unlock for the challenge is notably different. Instead of a cat eyeing a hairball, it seems to depict a cat eating the hairball back.