CryptoKitties is an Etherum-based cat raising sim game. Since the debut on Nov. 28, CryptoKitties blew the community with cat raising frenzy.

The unique fluffballs appear to trigger heated discussions among crypto users. By the end of Dec. 4, the historical in-app breeding, selling and buying cap reached $3 million in total. The surging popularity of CryptoKitties once occupied 20% of total Ethereum computations and 12% of total transaction volumes.

Ethereum has had issues of dealing with such a surge of the traffic, putting not only transactions of the Kitties but the whole system in an hour-long limbo. CryptoKitties officially announced to increase the birthing fee from 0.002 ETH to 0.015 ETH due to the network congestion.

To put things in perspective, in China’s Double 11 Shopping Day, Taobao could serve a daily transaction amounting to $2.47 million. On the contrast, at 4:00 pm, Dec.4, pending transactions on Etheruem was more than 15,000 with an expected transaction value of less than $2 million.

So why a million-dollar transactions could simply paralyze Ethereum?

It is primarily due to its architectural design.