USM mechanics overview

This page aims to list the most important mechanics introduced in the seventh generation, which began with the Sun and Moon versions, released in November 2016, followed by the Ultra Sun and Ultra Moon versions in November 2017. Unlike what you'll find on the USM Banlist page, everything here is directly tied to the games' core mechanics and do not depend on some specific community rules. Therefore, everything described below applies both on cartridge and simulators.

Z-Crystals

These are single-use items that allow their holder to unleash a Z-Move and, like Mega Stones, cannot be removed by Knock Off. Thus, a Water-type Z-Crystal allows the use of the Z-Power of a Water-type move. Simply put:

• In the case of an offensive move (physical or special), its power is increased and its secondary effects are removed. For example, Z-Flamethrower has a 175 base power and can no longer burn the target. In addition, a Z-Move never makes contact with the target.
• In the case of a status move, an additional effect is added to the move’s original effect. For example, Z-Tail Glow resets the user’s lowered stats in addition to raising its Special Attack by three stages. A Z-status move cannot be blocked by Taunt.

There is one Z-Crystal for each of the 18 types, as well as several species-specific ones that can only be used by one or more particular Pokémon. For example, Mewnium Z can only be used by Mew with Psychic, while Tapunium Z can only be used by the four guardians of Alola (Tapu Koko, Tapu Lele, Tapu Bulu, and Tapu Fini) with their signature move Nature’s Madness.

Z-Moves never fail and can break through protection moves such as Protect or Detect, dealing 25% of the damage they would normally inflict if the target had not protected itself.

A Pokémon affected by Taunt or Encore can still use its Z-Move.

Mega Evolution speed and ability mechanics

Unlike in Generation 6, the Speed and ability of Mega-Evolved Pokémon take effect immediately upon Mega Evolution. For example, Mega Swampert can immediately double its Speed upon Mega Evolving if rain is active, thanks to the ability Swift Swim. Pokémon that previously relied on Protect, such as Mega Diancie or Mega Beedrill, may now forgo it in some cases.

New Terrain mechanics

Another major change in Generation 7 is the introduction of abilities that automatically activate terrain effects. These already existed in Generation 6, but could only be triggered via moves and were therefore never used competitively. As a reminder:

• only one terrain can be active at a time.
• terrains last for 5 turns (8 turns if the user is holding the item Terrain Extender).
• terrain and weather can be active simultaneously.

The four guardians of Alola (Tapu Koko, Tapu Fini, Tapu Bulu, and Tapu Lele) each have a unique Ability that activates Electric Terrain, Misty Terrain, Grassy Terrain, and Psychic Terrain respectively upon entering the battlefield. Each terrain is associated with several effects, the main ones being as follows:

• Electric Terrain:
  • Electric-type moves are boosted by 50%.
  • Grounded Pokémon cannot be put to sleep.
• Misty Terrain:
  • Dragon-type moves are weakened by 50%.
  • Grounded Pokémon cannot be affected by any status condition.
• Grassy Terrain:
  • Grass-type moves are boosted by 50%.
  • Grounded Pokémon recover 6.25% of their maximum HP each turn.
  • Magnitude, Stomping Tantrum, and Earthquake have their power halved.
• Psychic Terrain:
  • Psychic-type moves are boosted by 50%.
  • Priority moves fail.

Boosts and reductions to move power only affect Pokémon that are in direct contact with the ground. As a result, Flying-type Pokémon and those with the Levitate Ability are not affected by these changes. For example, Zapdos will not benefit from the power boost to Electric-type moves under Electric Terrain, nor from the 50% damage reduction for Dragon-type moves under Misty Terrain.

IVs and Hidden Power

Although a Pokémon’s Hidden Power type is still determined by its IVs upon hatching or capture, it is now possible to maximize those IVs afterward. This does not affect the Pokémon’s Hidden Power type, but it means that any Hidden Power type can now be obtained while having all IVs set to 31.

Status condition changes

Burn

Burn now deals 6.25% of max HP per turn instead of 12.5%.

Paralysis

Paralysis now only halves the target’s Speed (instead of quartering it as in previous generations).

Confusion

The chance for a confused Pokémon to hurt itself in confusion is reduced from 50% to 33%.

Ability changes

Prankster vs Dark-type Pokémon

Dark-type Pokémon are immune to non-damaging moves used by Pokémon with the Prankster Ability.

Gale Wings

Talonflame’s Gale Wings Ability now only works when it is at full HP, which led to a sharp drop in usage and its eventual disappearance from the OverUsed tier.

"-ate" abilities

The power boost granted by the abilities Pixilate, Refrigerate, and Aerilate is now 20% instead of 30% as in Generation 6.

Drizzle, Drought and Sand Stream

Pelipper gains Drizzle, Torkoal gains Drought, and Gigalith gains Sand Stream. However, only Pelipper has become truly relevant in OverUsed, where it has largely replaced Politoed as the main rain setter on rain teams.

Gengar

Gengar loses Levitate, its only Ability since the introduction of Abilities in Generation 3, and gains Cursed Body instead. It therefore loses its Ground immunity but is now able to remove Toxic Spikes when entering the field.

Zapdos

Thanks to the move tutors in Ultra Sun and Ultra Moon, Zapdos can learn Defog while keeping the Static ability.

Move changes

Thunder Wave

Thunder Wave’s accuracy is reduced from 100% to 90%.

Sucker Punch

Sucker Punch’s base power is reduced from 80 to 70.

Destiny Bond

This move fails if it was successfully used on the previous turn.

Critical hits

The critical hit rate is reduced from 6.25% to 4.167%.

Summary

A red box means that the feature is absent from that generation, while a green box indicates that it is present.