On the 31st of March, Matthias Egli showed us the challenges of designing smart contracts, analyzing their vulnerabilities, and get hands-on experience in a real-world scenario. Matthias was the COO of ChainSecurity, an ETH spin-off that has helped secure more than 1 billion USD transiting through smart contracts. After a quick technical introduction on how to interact with a real-world blockchain, Matthias presented the participants with an actual smart contract. He challenged everyone to exploit its re-entrancy vulnerability. What followed was an intensive hands-on session during which everyone tried to multiply their wealth. Following this active part, Matthias went over more intricate attack patterns like flash-loans. The event concluded with a quick Q&A session about real-world applications of blockchains and newly trending topics such as NFTs.