In late October 2019, EIDOS, issued by the Enumivo team, launched on the EOS mainnet. The token adopted a "transfer-to-airdrop" distribution method: users would send at least 0.0001 EOS to the EIDOS contract, and the contract would return the same amount of EOS while airdropping a certain quantity of EIDOS. Public information at the time stated that this airdrop was expected to last 15 months. This mechanism transformed ordinary transfers into a repetitive action to acquire tokens, quickly driving up demand for EOS network CPU resources, leading to network congestion and a surge in resource prices.
How the EIDOS Airdrop Consumed EOS CPU
The EOSIO network requires transactions to consume resources such as CPU, NET, and RAM. CPU is primarily used for executing contracts and processing transactions. The trigger condition for the EIDOS contract was simple: a small transfer could simultaneously complete "returning EOS" and "claiming EIDOS." Therefore, users would repeatedly send transactions to the contract to obtain more EIDOS.
- Low transfer threshold: At least 0.0001 EOS was sufficient to trigger contract interaction.
- Repetitive transaction mining: Each interaction could yield EIDOS, incentivizing high-frequency transactions.
- Concentrated resource occupation: A large number of transactions simultaneously competed for CPU, causing ordinary transfers and DApp calls to queue up.
This design made the airdrop not just token distribution but also an externality event for network resources.
CPU Price Surge and Network Congestion
Public reports and on-chain data records at the time showed a surge in EOS network activity after EIDOS launched on October 31, 2019. Different sources had inconsistent metrics for CPU price increases: some claimed CPU prices rose by approximately 100,000% within 4 hours, while others stated that usage costs increased by about 10,000 to 20,000 times compared to before the airdrop. Due to different baselines and calculation methods, these figures should not be directly combined into a single metric.
According to public records, CPU prices once reached approximately 7.69 EOS/ms. Data from around November 8, 2019, also showed that about 95% of EOS transfer operations were related to the EIDOS contract, approximately 84% of EOS on REX was leased, and the number of active network users dropped from about 80,000 to below 20,000 in one day. All the above are historical data, reflecting the state during the event in 2019.
Congestion affected not only airdrop participants but also ordinary users: when CPU was insufficient, normal transfers, contract calls, and DApp interactions would slow down or fail.
Reactions and Controversies from All Parties
After the incident, exchanges, infrastructure providers, and project teams all responded. Coinbase at the time reported a decline in EOS transaction performance and increased staked CPU to restore client transactions. MYKEY stated at the time that to ensure smooth EOS usage for users, it had invested tens of thousands of EOS to lease resources on REX.
Jon Jordan of DappRadar at the time described EIDOS as "basically free money" and pointed out that such airdrops quickly consume blockchain resources. Adrian Krion of Chain Clash stated that the cost of using the EOS network increased by about 10,000 to 20,000 times, preventing many people from using the network.
From these reactions, the event had both aspects of a short-term arbitrage tool and a network stress test: it allowed some participants to quickly gain token returns, while also imposing the costs of rising resource prices and transaction failures on ordinary users.
Implications for the EOS Resource Model
The EIDOS event highlighted three issues with the EOSIO resource model.
- Resource pricing is highly sensitive: When transaction incentives are concentrated, CPU prices can fluctuate dramatically in a short period.
- REX leasing amplifies speculation: Those who lease resources in advance may gain arbitrage opportunities, while ordinary users face higher costs.
- Contract design requires externality assessment: Seemingly small interactions, if repeatedly triggered, can evolve into network-wide congestion.
From a historical perspective, the EIDOS airdrop did not change the fundamental operating logic of the EOS protocol itself, but it did alter the resource usage structure. At the time, the EOS protocol was still running; congestion arose from CPU resources being consumed by a large volume of transactions, rather than the protocol completely shutting down.
Risks and Historical Context
Public information records the maximum supply of EIDOS as 1 billion tokens. Around November 5, 2019, market data indicated EIDOS was valued at approximately $0.0667; it experienced short-term price fluctuations after its launch. At the time, some users obtained short-term token returns through high-frequency contract interactions, a practice referred to as "farming" by the community.
As a historical event, the EIDOS airdrop is a classic case of resource contention in a crypto network: airdrops can quickly concentrate transactions and can also turn on-chain resources into scarce commodities, leading to network congestion, increased costs, and degraded user experience simultaneously.
