Surprisingly, summoning a permanent sandstorm is not the only thing of value Hippopotas can accomplish. It also has the convenient ability to set up Stealth Rock and can do a decent job scouting from the lead slot, as well. However, expectations of Hippopotas should still be rather low. If it sets up Stealth Rock then dies, then its purpose has been served. If it sets up Stealth Rock, poisons or significantly damages something, and manages to scout a couple of members of the opposing team, then a standing ovation may be in order.
Hippopotas is notable only for the ability Sand Stream, which makes it the only Pokemon in UU play who can trigger a permanent sandstorm. This set attempts to make the most of Hippopotas's short lifespan by giving it the opportunity to status or scout the opponent's team as a lead. Hippopotas's primary goal, however, is to set up Stealth Rock, which should generally be made a priority over everything else. Yawn and Roar are both effective ways of scouting opponents, one of the few things Hippopotas does well. Protect can block Fake Out and trick U-turners into getting put to sleep when used in conjunction with Yawn. Meanwhile, Toxic allows Hippopotas to damage bulky Pokemon, while Earthquake is better versus fragile Pokemon and Taunt users. The EVs let Hippopotas survive a Fake Out and Return from Ambipom while allowing for maximum attack power should you opt to use Earthquake. The nature and Speed IV allow it to be slower than all Snover, so that sandstorm takes precedence over hail if the two leads are opposing each other.Team Options & Additional Comments >>>
Hippopotas's list of viable moves does not extend far beyond those already mentioned. Put bluntly, this is because its base stats are severely lacking in every category. Its offensive movepool isn't terrible, sporting Crunch, Double-Edge, and Superpower in addition to Earthquake, although Stone Edge's absence is slightly unfortunate. The bad news is that Hippopotas will probably only get one or two chances to strike, and its base 72 Attack really doesn't go a long way. For this reason Toxic is quite often the better method of damaging bulkier foes over the long run. Curse and Slack Off are welcome additions to many movepools, but again, Hippopotas's defenses make them nearly worthless.
Chesto Berry can be used over Focus Sash, but with the departures of Roserade and Yanmega from UU, sleep-inducing moves are neither common nor worth relinquishing Focus Sash to prevent. Chesto Berry gets the edge over Lum Berry because Hippopotas typically won't live long enough to see Will-O-Wisp or Toxic do significant damage, so negating them with Lum Berry is useless. Leftovers is another option, but again, Focus Sash will typically do a much better job of prolonging Hippopotas's life.
The given EVs allow Hippopotas to maximize its attack power while still surviving Life Orbed Ambipom's combination of Fake Out and Return 100% of the time. If you are running Protect, feel free to ignore this EV spread and redistribute the EVs between Attack and Defense as you see fit.
Checks and Counters
Taunt reduces Hippopotas to a horribly one-dimensional threat, preventing it from doing anything but using Earthquake. Trick leads can cripple Hippopotas in a similar manner, although they won't necessarily be able to stop it from setting up Stealth Rock. Essentially any anti-lead or strong special attacker should be able to 2HKO it. As expected, Hippopotas is not a difficult Pokemon to counter by any stretch of the imagination, but so long as it gets Stealth Rock in play it has done its job.