In Diamond & Pearl, there are several attacks that do damage on the Pokémon when they are switched in as opposed to when you actually attack. These are very handy to cause damage to your opponents before you even get a chance to attack and to stop them from casually switching out without them having any drawbacks to it. This page is set out to show the true extent of these attacks and how much damage they do

Spikes Spikes is the original Entry Hazard move. As it holds the Ground Type, it does have the problem that it does not affect Pokémon of the Flying Type or Pokémon with the Levitate Ability The damage that is given through Spikes is determined by the amount of layers that you place: Amount of Layers HP Taken 1 Layer 1/8 of Opponent's Maximum HP 2 Layers 1/6 of Opponent's Maximum HP 3 or more layers 1/4 of Opponent's Maximum HP However, on top of this, it is possible for the opponent to dispell the Spikes if the opponent uses the move Rapid Spin

Toxic Spikes Toxic Spikes is the only Entry Hazard attack that does not afflict damage on the Pokémon straight away. Instead, it inflicts them with the Poison Condition. It does not affect Pokémon of the Flying Type, Steel Type, Poison Type or Pokémon with the Levitate Ability The damage that is given through Spikes is determined by the amount of layers that you place: Amount of Layers Effect 1 Layer Poison's Opponent 2+ Layers Badly Poison's Opponent However, on top of this, it is possible for the opponent to dispell the Toxic Spikes if they send out a Poison Type Pokémon

Stealth Rock Stealth Rock's damaging methods are rather unique. Instead of doing a set amount of damage for the amount of layers given, it instead is based on the opponent's type. The attack is a Rock Type attack so the damage is based upon the opponent's Weakness to it. For a full chart, click here Type Effectivness Damage x0.25 Effective 1/32 of Max HP (3.125%) x0.5 Effective 1/16 of Max HP (6.25%) x1 Effective 1/8 of Max HP (12.5%) x2 Effective 1/4 of Max HP (25%) x4 Effective 1/2 of Max HP (50%) This shows that Stealth Rock can easily help defeat the opponent with little effort if they use a Pokémon such as Charizard or Articuno