Entry Hazards in Pokémon Battles: Stealth Rock, Spikes, and More

🪤 Entry hazard basics

In Pokémon battles, entry hazards are field effects that damage or hinder opposing Pokémon when they switch in. They can chip away at HP, inflict status, or lower stats. Entry hazards can play an important role in controlling the battle especially in single battles.

• Stealth Rock: Damages all switch‑ins based on their Rock‑type matchup. For exact damage see table below.
• Spikes: Damages grounded switch‑ins. Stacks up to three layers for increased damage.
  (1 layer: 12.5% · 2 layers: 16.67% · 3 layers: 25% of max HP)
• Toxic Spikes: Poisons grounded switch‑ins, two layers badly poison instead. Removed when a poison type Pokémon switches in on them.
• Sticky Web: Lowers Speed of grounded switch‑ins by one stage.

Example: Talonflame is a Fire/Flying type Pokémon (both types weak ot Rock), which makes it 4× weak to Rock-type moves. Therefore Stealth Rock will remove 50% of its maximum HP upon switching in.

🧹 Removing and Preventing hazards

Certain Moves, Abilities and items interact with hazards.

• Rapid Spin: Removes hazards from your side; from Gen VIII onward, boosts user’s Speed by 1 stage.
• Defog: Removes all hazards from both sides.
• Court Change: Swaps hazards (and other field effects like screens) between sides.
• Mortal Spin: Removes hazards and poisons the foe.
• Magic Bounce: Reflects hazard‑setting moves (and other status moves) back to the user.
• Heavy‑Duty Boots When a Pokémon has this item it ignores entry hazards.

📌 Strategy tips

• Entry hazards are more important in Single battles than Multi since Single battles on average have more turns and switches than Multi battles.
• Use hazards to punish frequent switching and break down defensive cores and stall teams.
• Combine multiple hazards to pressure the opponent into fewer safe switches.
• Keep hazard removal in mind when teambuilding to avoid being worn down.
• Items like Heavy‑Duty Boots are especially good on Pokémon with a 4x weakness to rock (Because of their vulnerability to stealth rock).

🕰️ The history of entry hazards in Pokémon

Key additions and changes to entry hazards across generations.

Generation II

• Spikes introduced (single layer only).

Generation III

• Spikes Spikes now stack up to three layers.

Generation IV

• Toxic Spikes introduced.
• Stealth Rock added;

Generation V

• Magic Bounce introduced, reflecting hazards.

Generation VI

• Sticky Web introduced; Defog now removes hazards from both sides.

Generation VIII

• Rapid Spin gains Speed boost; Heavy‑Duty Boots introduced.

Generation IX

• Mortal Spin added as hazard removal and status move.