The Binding of Isaac: Rebirth – Binding of isaac: how to unlock swallowed penny!

How to unlock it

 
To unlock swallowed penny you must complete challenge 15: ‘slow roll’. In this challenge you start with 100 damage and you start as Isaac. You also start with the items cupid’s arrow, my reflection and Polyphemus. To beat the challenge you need to defeat Mum, you start with this challenge when you first buy the game. 
 
Cupid’s arrow 
Cupid’s arrow makes Isaac’s tears pierce enemy’s but not obstacles such as rocks or mushrooms. Cupid’s arrow is already unlocked in every save file. 
 
My reflection 
My reflection makes Isaac’s tears travel a short distance, then they return to him. My reflection is already unlocked on every save file.https://www.youtube.com/watch?v=xQntkBFHJio 
Polyphemus 
Polyphemus is a great item which gives a massive damage boost at the cost at your tear firing rate. Polyphemus is already unlocked on every save file. 
 
All of the items in bold are the items which are used in the challenge. Treasure rooms cannot be found in challenge 15 but shops are still on each floor. I hope this guide was helpful, I will be making more guides soon. Goodbye! 
 

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