Spike

To Spike is to cause a large influx of something (like a spike in a curve). Spiking can refer to many things, such as spike healing (healing in large chunks), spike damage (causing great spurts of damage) or spike energy (to regenerate energy in chunks).

A spiker is a player who inflicts massive amounts of damage to a single target in a short period of time, with the goal of taking them down quickly. This is in contrast with a Nuker, whose objective is to deal large amounts of damage to multiple targets over a period of time. A nuker overwhelms the opposing healers' energy supply, while a spiker would overwhelm the healers' immediate healing capabilities.

PvP spikes
Spiking first came into widespread use with teams of elementalists, typically Air Magic specialists, who all bombarded the target with a single, high damage spell. Since then the metagame has produced many other spikes over the years, and some worthy of mention are:
 * Ranger spikes, which used the Ranger profession, combining Dual Shot with either Punishing Shot, Savage Shot, or less commonly Quick Shot. A Necromancer or Mesmer/Necromancer using Order spells (like Order of Pain) was added to greatly increase the damage of the spike.
 * Blood spikes, which used the Necromancer profession, combining high-damage and Life stealing spells such as Shadow Strike (and it's duplicate Lifebane Strike), Vampiric Gaze and Oppressive Gaze.
 * FoC spikes, which also used the Necromancer profession, combining the elite skill Feast of Corruption and AoE Hexes such as Suffering.
 * SF spikes, which use the powerful elementalist elite Searing Flames to inflict mass burning and damage.
 * Para spikes, which use the Paragon profession, combining high damage spear attacks such as Spear of Lightning and Paragon attack and defence Buffs such as Anthem of Flame.

Spikers are popular in PvP because they can quickly kill opponents, weakening the opponents attack and healing capabilities. As the match goes on and players accrue death penalty, they become more susceptible to spiking, creating a slippery slope effect for the opposing team. Also, because of the relatively small number of skills one must devote to spiking, there is much room left over for defensive skills. For example, an Air Elementalist could bring Lightning Orb and Lightning Strike to spike with, then use the rest of his skill bar for skills such as Blinding Flash, Ward Against Melee and Gale.

PvE spikes
Spiking can also occur in PvE. Some Bosses are capable of dealing in excess of 200 damage in a single spell or attack, and this works just like a spike in PvP. In Hard Mode, damage is increased and many bosses will be able to kill a player in a single hit. Ritualists are particularly adept at countering PvE spikes (see below). Some of the Bosses capable of dealing this much damage are Sskai, Dragon's Birth, Birneh Skybringer and Korr, Living Flame, to name but a few. Multiple hit attacks are particularly lethal in Hard Mode, and bosses such as Wing, Three Blade can destroy an entire party in seconds if they are not properly prepared.

Counters

 * The best way to counter a spike build is by using interrupts. This will cause the spike to deal less damage, allowing your monks more time to deal with the spike. Skills such as Gale, Mind Shock, Cry of Frustration, Leech Signet, Distracting Blow, or other interrupts can be used to disrupt a damage dealer in midspike. Additionally, interrupting a spike may cause the spiking team to lose concentration and hinder the ability to prepare for another spike.
 * Protection Prayers are a good neutralizer to spike damage. They contain spells that limit damage to allies like Protective Spirit, Life Bond and Life Barrier as well as spells that deflect some or all damage such as Reversal of Fortune and Mark of Protection. Spirit Bond is also good against spikes, as is Life Sheath.
 * Bringing a monk with Infuse Health, which, with its 1/4 second activation time and large heal, can often be cast in midspike with a big enough heal to outlast the spike. This monk should be well-protected, because once the spiking team realizes what is happening they will likely focus on the infusing monk.
 * In GvG one can also split against a spike team. Because most spikes builds require all of the offense to be present to score kills, they will only be able to engage one of your split teams at a time. This will leave your other group free to run flags or kill NPCs without hindrance.
 * Ritualists are also good against spikes. Skills such as Union and Shelter can absorb a large portion of a spike. Ritualists are also particularly adept at preventing spikes in PvE (as mentioned above).