Here is my submission, a different Calm Mind set than the one proposed and the one already on-site.
Entei @ Leftovers
Trait: Pressure (Flash Fire upon release)
EVs: 252 HP/4 Def/252 SpD
Nature: Calm/Sassy
-Lava Plume
-Calm Mind
-Hidden Power Grass/Hidden Power Water
-Extrasensory/Stone Edge/Shadow Ball
This is the special tank version of Entei that relies on natural bulk to set up rather than Substitutes. Lava Plume is the best STAB because of its nice burn rate, patching up the not-so-good physical defense, letting Entei set up more, with Calm Mind. The coverage options have some preference in them. Hidden Power Grass takes care of most of Entei's own weaknesses (obviously replace with Solarbeam if on a sun team), to Pokemon such as Kabutops and Rhydon on the switch in. However, if your team has a lot of Fire weaknesses and not as many Water weaknesses, then Hidden Power Water is the next best choice (e.g., if the rest of the team is Cradily, Escavalier, Torterra, Amoonguss, and Magneton, HP Water would be better). Extrasensory is good for Fighting-types, especially Hariyama, as it would LOVE to get burned by Lava Plume, and also for the occasional Poison-type that is hit harder by it than Lava Plume. Stone Edge could be used to make this a mixed set and hit many Pokemon such as Magmortar, Charizard, and Aerodactyl (use this with HP Grass), and Shadow Ball is a bit situational, but leaves good dents in Uxie, Sigilyph, and Misdreavus.