Why does this team work?
When I first started doing pet battles I chose what ever pets suited my liking. The three I had started with were Singing-sunflower, Lunar-Lantern, and Darkmoon-tonk. Soon I realized when doing a couple random battles(Around level 10), that those pets bought through the Blizzard online store were very strong even versus rare level pets. To be able to combat these "overpowered" pets were left with two options. Either buy these particular pets and battle them heads up , which I could not do due to money limitation, or build a team that directly counters the possibilities of these pets.
So I started looking for pets with abilities that did extra damage vs Humanoids, Elementals, and Mechanical battle pets. After a bit of careful consideration I had settled on a team of Darkmoon-tonk, Lost-of-Lordaeron,and Lava-crab . This worked for a few battles until again I realized that the pets I had chosen were very limited to singular set ablities types. Often when pvping, I was beat out on a damage per second race versus even matched pets.
I began to do a bit more research and testing of different pets, and after doing a few additional pvp pet battles. A new type of strategy dawned on me, one that consisted of damage over time and health gain. That is how I settled on the current level 25 team shown above. Finding pets that both had an ability to beat those pesky Battle Store pets, but also were hearty and did good damage was trickey.
Oily Slimeling can be found in the pools of water in Scalding Pools, Borean Tundra. Desert Spider can be found in a lot of different zones, including Desolace, Tanaris, Uldum, and Silithus. Darkmoon-tonk can be bought from Lhara on Darkmoon isle for 90 prize tokens.
Looking first at the abilities of Oily Slimeling the combination of Creeping Ooze and Acidic Goo is what makes this pet so dangerous. The extra 25% damage from Acidic goo also applies both to the healing affect from absorb and the increasing damage of Creeping Ooze. Oily Slimeling is very good stand alone pet because of the pairing of these third skills.
Second on the list is Desert Spider, the power this particular battle pet comes from the combination of Brittle Webbing and Leech Life. As it says in the text of Brittle Webbing it counts as a "Web" effect, allowing a follow up attack Leech Life to heal double the damage. What also makes Brittle Webbing quite interesting if opponent's pets have abilities that allow them to attack more than once a round , the damage from Brittle Webbing does damage for each one of those hits.
Third is the pet that has stuck with me through my experimentation, even the times I took him out of the team, was quickly added back in. The Darkmoon Tonk, being a mechanical pet comes back with 25% life once slain in an battle. This pet is much more in that it is a tank both literally and figuratively. Both the abilities Shock and Awe, and Ion Cannon are very high damage attacks. It is not uncommon to see Darkmoon Tonk get lucky with Ion damage crit on a Beast-type pet for for upwards of 1500 damage! The high damage attacks are also the downfall of Darkmoon Tonk as both have a lengthy cool-down period leaving the tonk with a small damage attack for a couple rounds.
This team with the high damage and the healing effects make it quite strong team overall. The only pets I have found that gave this team trouble as I battled through Pandaria. Were teams with a Dragonkin, that had both Elemental attacks and Dragonkin attacks that did double damage versus my Magic and Mechanical pet respectively . The second pet type that gave the team trouble were Aquatic pets that had both a shell to reduce damage and a heal over time. This counter set-up locked out both Spider and Slimeling since they could not do enough damage to actually kill the Aquatic pet. Luckily this type of situation is why the Darkmoon Tonk shines as it has enough power to punch through the defenses.