Three developers out of Onther Inc in South Korea released a research paper on Plasma EVM, a version of Plasma that can support "smart contracts." Sounds great, but there are some security issues.
Plasma MVP, or Minimum Viable Plasma, is the most well-known and discussed iteration of Joseph Poon and Vitalik Buterin's concept of Plasma, first laid out in an August 2017 working paper[1]. In that paper, it's referred to as a "framework for incentivized and enforced execution of smart contracts which is scalable to … be able to represent a significant amount of decentralized financial applications worldwide." Plasma MVP has yet to be launched on the main chain, but when it is, MVP will enable a (relatively high) degree of scalability for transfers of digital assets, but that's about it. No EDCCs (aka smart contracts).
A recently released research paper[2] by Carl Park, Aiden Park, and Kevin Jeong of Onther Inc. titled "Plasma EVM" seeks to move closer to Poon's vision by enabling execution of the Ethereum Virtual Machine's Turing-complete computation power. If successful, an EVM-enabled plasma chain would allow[3] for EDCCs, permit existing clients like Go Ethereum and Parity to run the chain, and make Ethereum development tools available for use.
However, Plasma EVM is very much in its early stages. It's unclear how much time or bandwidth has already gone into the recently released research paper, but the authors make clear that there are security issues and technical challenges that must be addressed before it could be considered viable enough for testing.
For one, the developers point to one known attack possible under their current model where the Plasma operator could withhold blocks from finalization. They suggest a method for addressing this concern
