He ran as fast as sonic across the map for one so even if you flash he already caught up to where you flashed, insta cc'd, and bashed to death for 2 seconds while he lifetseals back to full. there is no counter play to this. If you're an immobile champion you're gonna get destroyed. He's broken as all hell and needs to be nerfed on that movement speed and damage. That's just fucking ridiculous.