- Speed doubles in rain.
- Prevents critical hits.
- Boosts Speed by 1 stage and lowers Defense by 1 stage when hit by a physical move.
Level 100 Statistics (see level 5, 50, 100)
When looking at Omastar's stats, it seems to be just another one of many bulky Water-type attackers. However, Omastar has access to what is arguably the best boosting move in the game, Shell Smash. With this gem of a move, Omastar is able to fix its low Speed and boost its already great Special Attack stat to incredible levels in just one turn of setup. Omastar also has access to both Stealth Rock and Spikes, thus allowing it to step outside of its normal sweeping role with decent success. It can even use Shell Smash along with one of these entry hazards to make for quite the flexible Pokemon. Omastar has some very useful resistances as well, including an all-important 4x Fire-type resistance that lets it use Entei, one of the most common Pokemon in the tier, as easy setup bait.
However, Omastar is held back by a few glaring flaws that prevent it from dominating the tier. Its Speed is low; even after a Shell Smash boost, Choice Scarf Pokemon such as Rotom and Manectric can still effortlessly revenge kill Omastar and limit the damage it can do in a match. A mediocre Special Defense combined with weaknesses to common attacking types such as Grass, Electric, and Fighting makes it quite difficult for Omastar to successfully set up and pull off a sweep. Nevertheless, Omastar is a very potent sweeping threat to look out for in RU. Omastar only requires one turn to lay waste to entire teams, so tread lightly around it.
This is the set that made Omastar the feared sweeping threat it is today. With just a single turn, Omastar is capable of boosting its Speed and Special Attack to very threatening levels, and it's all thanks to Shell Smash. After using this, Omastar can make use of its solid three move coverage to ravage the opposing team. Omastar's STAB move comes down to the age old argument of power vs. accuracy. Since this Omastar is used more as a sweeper, Surf is preferred for the reliability it brings and still has sufficient power in most situations. Hydro Pump is an option in order to muscle past Pokemon like Cryogonal and Uxie, but an untimely miss can mark the premature end of a sweep. Ice Beam is useful to hit the many Grass-types in RU, including Rotom-C, Sceptile, and Amoonguss. Hidden Power Grass rounds off Omastar's coverage and allows it to deal with opposing Water-types such as Slowking, Lanturn, and Alomomola.
Team Options & Additional Comments >>>
Instead of using a free turn to set up Shell Smash and sweep the opposing team, this Omastar uses free turns to litter the other side of the field with entry hazards. Omastar might lack the Speed of other fast Spikers such as Smeargle and Scolipede, but a combination of Weak Armor and Icy Wind can mitigate this. Spikes is the main entry hazard on this set due to its lesser distribution and Omastar's ability to get two layers up almost every time. Scald generally gets the nod for Omastar's STAB move as the burn chance can deter physical attackers from attempting to set up on it. Hydro Pump is an option for the much greater power, but Omastar's primary concern should be to get entry hazards up. Icy Wind is nice to slow down faster Pokemon switching in such as Manectric, Sceptile, and Galvantula. Ice Beam is a solid alternative to get the harder hit on Pokemon such as Druddigon and Amoonguss, which are already slower than Omastar. The last move gives Omastar added utility. Stealth Rock allows Omastar to support its team even more and free up a teamslot to cover other things. However, Shell Smash is an option if you don't need Omastar to use Stealth Rock. Although it looks odd, Shell Smash allows Omastar to weaken the opposing team and have more flexibility in how it's played outside of the lead position. Note that you should always use Ice Beam if you opt for Shell Smash as you will now have a way of boosting Omastar's Speed reliably.
Team Options & Additional Comments >>>
This set takes advantage of Omastar's great base 125 Defense and key resistances to Fire-, Normal-, and Flying-type moves to check dangerous threats and supply entry hazards for its team. Spikes is the main entry hazard on this set, as it sets Omastar apart from other physical walls, such as Rhydon and Steelix. Stealth Rock comes next as it makes it difficult for many of the threats Omastar checks to outlast it, since many are weak to Stealth Rock. Scald is Omastar's STAB move with the ever-infuriating 30% chance to burn the opponent. Ice Beam rounds off the set by giving Omastar a way to try and fend off Grass-types that try to come in on it.
Team Options & Additional Comments >>>
Most of the relevant options in Omastar's movepool have already been covered, but there are a couple of other things to consider. Omastar could use Choice Specs to hit really hard right off the bat, but Omastar will generally want to use a free turn to set up a Shell Smash or a layer of entry hazards. AncientPower and Hidden Power Rock can be used for a Rock-type STAB move, but this is usually not needed due to Omastar's great three move coverage. Knock Off can be used on the defensive set to remove items off of Pokemon such as Roselia and Ferroseed. Hidden Power Fire is an option if you're really having issues against Jynx or Ferroseed, but Hidden Power Grass is usually too important to give up.
Checks and Counters
When trying to counter Omastar, it's generally best to use a Choice Scarf Pokemon that can outspeed and OHKO it at +2. Rotom and Manectric are the best two options for this as their STAB Volt Switches can OHKO Omastar or build momentum for their team if Omastar switches out. Primeape isn't a very common Pokemon, but it can outspeed +2 Omastar if it has a Choice Scarf equipped and it can defeat Omastar with STAB Close Combat. However, they will fail to outspeed if Omastar is able to get a Weak Armor boost on top of a Shell Smash boost. Lanturn is a solid defensive response as it can survive even a +2 Life Orb-boosted Hidden Power Grass and proceed to OHKO Omastar with Volt Switch. Depending on the set it's running, Slowking can handle Omastar decently well. Slowking's Choice Specs set only loses to Life Orb variants while defensive Slowking only loses to Lum Berry variants of the Shell Smash set. Roselia fears a +2 Life Orb Ice Beam, but it can take any other hit and proceed to OHKO Omastar with its STAB Giga Drain. If Omastar lacks a Life Orb, Jynx can check it thanks to its immunity to Water and Ice-type resistance. Ferroseed can beat Omastar if it packs Seed Bomb, but both must be wary of the rare Hidden Power Fire.
A powerful priority user can limit the damage Omastar can cause. Hitmonlee and Hitmonchan are the most notable since their STAB Mach Punch can hit Omastar for super effective damage. Hitmonlee is also able to threaten with a counter-sweep with Unburden-boosted Speed after it activates its Fighting Gem with Mach Punch. Absol and Spiritomb can utilize their powerful STAB Sucker Punch, but they will need Omastar to be weakened a little due to its high base 125 Defense. Each of Omastar's hazard sets can be limited through the use of Rapid Spin. Kabutops and Cryogonal are by far the best spinners in the tier and Cryogonal even matches up well against Omastar in most cases. Grass-types such as Amoonguss, Lilligant, and Roselia can easily threaten the defensive set due to its lack of offensive investment. Finally, you can always resort to constant offensive pressure to limit the chances Omastar has to set up. However, you must be very careful if you rely on Pokemon like Entei and Swellow to provide this general pressure, as Omastar can easily use their STAB moves as setup bait, and all Omastar needs is one turn to wreak havoc for the rest of the match.