This is my first-ever attempt at making a competitive team. (It's to challenge Tidal Wave in the Gym Challenge.) Some of the movesets and/or EV spreads are taken directly from Smogon, but I wrote all of the descriptions myself. This might be completely awful- I really don't know. Please rate and help!
Tornado (Hippopotas) @ Leftovers
Nature: Impish (+Def, -SpAtk)
Ability: Sand Stream
EVs: (212/180/52/0/20/44)
Moves:
-Stealth Rock
-Earthquake
-Crunch
-Slack Off
Description: Tornado is the team lead and pretty much a necessity for Sandstorm teams. Stealth Rock is there because it's pretty much a starter necessity. Earthquake is for general STAB damage to take advantage of Hippopotas' respectable 16 Attack with EVs. Crunch deals a little more damage to Ghost and Psychic types, but I'm not very attached to it and I want a better move. Slack Off recovers a half of the total HP, and in conjunction with Leftovers, Tornado should be able to survive a bit of a fight. The EVs look pretty strange, but adding extra EVs to level 5 Pokemon often doesn't increase the stat.
So far, we have a Sandstorm set up and a weakness to Water, Grass, and Ice types. I'm going to ignore the weakness for a moment and set up a sweeper that can use the Sandstorm like crazy, though.
Splatter (Drilbur) @ Life Orb

Tornado (Hippopotas) @ Leftovers
Nature: Impish (+Def, -SpAtk)
Ability: Sand Stream
EVs: (212/180/52/0/20/44)
Moves:
-Stealth Rock
-Earthquake
-Crunch
-Slack Off
Description: Tornado is the team lead and pretty much a necessity for Sandstorm teams. Stealth Rock is there because it's pretty much a starter necessity. Earthquake is for general STAB damage to take advantage of Hippopotas' respectable 16 Attack with EVs. Crunch deals a little more damage to Ghost and Psychic types, but I'm not very attached to it and I want a better move. Slack Off recovers a half of the total HP, and in conjunction with Leftovers, Tornado should be able to survive a bit of a fight. The EVs look pretty strange, but adding extra EVs to level 5 Pokemon often doesn't increase the stat.
So far, we have a Sandstorm set up and a weakness to Water, Grass, and Ice types. I'm going to ignore the weakness for a moment and set up a sweeper that can use the Sandstorm like crazy, though.

Splatter (Drilbur) @ Life Orb