Check
Reuniclus @ Leftovers
Ability: Magic Guard
EVs: 252 HP / 200 Def / 56 SpD
Bold Nature
- Calm Mind
- Psyshock
- Focus Blast
- Recover
Reuniclus avoids the 2hko from any of Lucario's moves (unless it's running Crunch) and proceed to OHKO back with Focus Blast.
252+ Atk Life Orb Lucario Iron Tail vs. 252 HP / 200+ Def Reuniclus: 188-224 (44.3 - 52.8%) -- guaranteed 3HKO after Leftovers recovery
+2 252+ Atk Life Orb Lucario Iron Tail vs. 252 HP / 200+ Def Reuniclus: 378-446 (89.1 - 105.1%) -- 31.3% chance to OHKO
252+ Atk Life Orb Lucario Crunch vs. 252 HP / 200+ Def Reuniclus: 203-239 (47.8 - 56.3%) -- 29.7% chance to 2HKO after Leftovers recovery
+2 252+ Atk Life Orb Lucario Crunch vs. 252 HP / 200+ Def Reuniclus: 403-476 (95 - 112.2%) -- 68.8% chance to OHKO
(If you're that worried about Crunch, run Colbur Berry)
So yeah, you're completely safe unless Lucario has already boosted.