CryptoKitties is the newest craze capturing the attention of the cryptocurrency community. Whether one thinks it’s the greatest creation ever, or doesn’t understand how something so dumb is so popular, everyone is talking about it. With this popularity, however, comes a price. So many people are buying, selling, and breeding CryptoKitties that the Ethereum blockchain is struggling to keep up with all the activity.

CryptoKitties captured everyone’s attention when its Genesis Cat sold for 250 ETH. Since then, activity on the game has continued to grow. As of right now, CryptoKitties is the most active smart contract on the Ethereum network, accounting for over 16% of all Ethereum transactions. EtherDelta’s contract is the second most active, currently responsible for over 12% of all transactions.

With an explosion of new activity, the Ethereum blockchain is becoming increasingly backed up with unconfirmed transactions. Recently, the number of unconfirmed Ethereum transactions has remained consistently above 15,000. To put that in context, each block

 typically processes between one and two hundred transactions. Prior to the launch of CryptoKitties, unconfirmed transactions averaged about 2,000.

For CryptoKitties users, this ever-increasing backlog has resulted in rapidly increasing wait times to breed and transfer cats, as the births of their kittens remain stuck in limbo as a result of unconfirmed transactions. This is more than just frustrating, as it also allows users to exploit the system by double spending breeding transactions

 if their unborn kittens have bad genetics. Essentially, malicious users can abort their unborn kittens until they get the ideal offspring.

Fortunately, CryptoKitties has responded by increasing the cost of birthing a kitten to .015 ETH. This cost is considered a “birthing fee” which is paid to the entity that confirms the transaction. With current gas prices, this fee results in a small profit to whoever confirms the birth. The way it is intended, this change will allow the community to stop bad actors by confirming kitten births before they can be re-rolled.

While some individuals are firm believers that CryptoKitties is merely a fad that will burn out as quickly as it grew, there are thousands of active CryptoKitties users who are enjoying participating in the game. After all, the kittens they can call their own are very cute.