Although burn could really hurt sableye and it just can't spam snarl forever. Slowbro just has to spam calm mind until snarl misses, and the special defence rises in the prosses. Not to mention it has shell armor so it cant get struck by a critical hit.Mega-Slowbro can't really do much to mega-sableye. A face on attack is "0 SpA Mega Slowbro Scald vs. 252 HP / 252+ SpD Mega Sableye: 72-85 (23.6 - 27.9%) -- 87.4% chance to 4HKO" meaning a critical hit won't ohko, and probably won't do enough damage for a regular attack after all the modifiers from calm mind and snarl to 2OHKO. Meanwhile, Scald has a 30% chance to burn, while Will-o-wisp has an 85% chance, which should mean, that Slowbro is being widdled down first. Anyhow, Mega-sableye won't have to recover nearly as much as Mega-slowbro because mega-slowbro's attacks are getting weakened by Snarl, which also gets buffed by calm mind and has the luxury of being super effective. My experience usually has Mega-Sableye coming out on top of Mega-Slowbro.