Fundstrat co-founder Tom Lee has issued a rare bearish warning for Ethereum, cautioning that a "brutal sell-off" in South Korean equities could spill over into the cryptocurrency market, causing short-term pain for ETH. South Korea's benchmark KOSPI index plunged over 6% on Tuesday, October 13, driven by a massive sell-off in technology and semiconductor stocks, including Samsung Electronics and SK Hynix. The decline was partly attributed to concerns over increased competition from Chinese chipmaker ChangXin Memory Technologies (CXMT). The Philadelphia Semiconductor Index also fell 2.67% in the last session.