It's +6 though and skarm and ferro won't enjoy taking a move from that guy.
Well it's not OU worthy for sure, but in UU that thing wrecks everything.
Megavenusaur won't enjoy taking a +6 return to the face either.
+6 252+ Atk Slurpuff Play Rough vs. 252 HP / 252+ Def Ferrothorn: 138-163 (39.2 - 46.3%) -- guaranteed 3HKO
0 SpA Slurpuff Flamethrower vs. 252 HP / 0 SpD Ferrothorn: 204-240 (57.9 - 68.1%) -- guaranteed 2HKO
0 Atk Ferrothorn Gyro Ball (150 BP) vs. 4 HP / 0 Def Slurpuff: 348-410 (113.7 - 133.9%) -- guaranteed OHKO after Unburden
+6 252+ Atk Slurpuff Play Rough vs. 252 HP / 232+ Def Skarmory: 133-157 (39.8 - 47%) -- guaranteed 3HKO after Leftovers recovery
0 SpA Slurpuff Flamethrower vs. 252 HP / 0 SpD Skarmory: 152-180 (45.5 - 53.8%) -- 3.9% chance to 2HKO after Leftovers recovery
+6 252+ Atk Slurpuff Play Rough vs. 252 HP / 252+ Def Mega Venusaur: 144-171 (39.5 - 46.9%) -- guaranteed 3HKO
+6 252+ Atk Slurpuff Return vs. 252 HP / 252+ Def Mega Venusaur: 219-258 (60.1 - 70.8%) -- guaranteed 2HKO
0 SpA Mega Venusaur Sludge Bomb vs. 4 HP / 0 SpD Slurpuff: 290-344 (94.7 - 112.4%) -- guaranteed OHKO
+6 252+ Atk Slurpuff Play Rough vs. 252 HP / 0 Def Heatran: 110-130 (28.4 - 33.6%) -- 97.2% chance to 4HKO after Leftovers recovery
+6 252+ Atk Slurpuff Return vs. 252 HP / 0 Def Heatran: 167-197 (43.2 - 51%) -- guaranteed 3HKO after Leftovers recovery
4 SpA Heatran Lava Plume vs. 4 HP / 0 SpD Slurpuff: 138-163 (45 - 53.2%) -- guaranteed 2HKO
I'm not sure what kind of teams you are wrecking with that thing lol. UU has a shitton of Fire-types too, and a Scarfed Victini or Mienshao can outspeed Slurpuff and kill it. 486 Speed with Adamant is nothing special, and with Jolly you lose quite a bit of power.