Backfire
Main ball spiker with a focus on caster punishment with 
BackfireBackfireMesmer / Domination Magic / Hex SpellE 15Cast 3Recharge 20For 10 seconds, whenever target foe casts a Spell, that foe takes 35..140 damage..
Build
Arcane EchoMesmer / Enchantment SpellE 15Cast 2Recharge 20If you cast a Spell in the next 20 seconds, Arcane Echo is replaced with that Spell for 20 seconds. Arcane Echo ends prematurely if you use a non-Spell skill.
Energy SurgeElite / Mesmer / Domination Magic / SpellE 5Cast 2Recharge 15Target foe loses 1..10 Energy. For each point of Energy lost, that foe and all nearby foes take 9 damage.
Unnatural SignetMesmer / Domination Magic / SignetCast 1Recharge 10Target foe takes 15..75 damage. If that foe is under the effects of a hex or enchantment, foes adjacent to your target take 5..50 damage.
Ebon EscapeEbon Vanguard rank / SpellE 5Cast 0.25Recharge 10Shadow Step to target other ally. You and that other ally are healed for 70..110 health.BackfireMesmer / Domination Magic / Hex SpellE 15Cast 3Recharge 20For 10 seconds, whenever target foe casts a Spell, that foe takes 35..140 damage.
MistrustMesmer / Domination Magic / Hex SpellE 10Cast 2Recharge 12For 6 seconds, the next spell that target foe casts on one of your allies fails and deals 10..100 damage to that foe and all nearby foes.
"You Move Like a Dwarf!"Norn rank / ShoutE 10Recharge 10Target foe is knocked down and takes 44..80 damage. When that foe gets up, it is Crippled for 8..15 seconds.
Wastrel's DemiseMesmer / Domination Magic / Hex SpellE 5Cast 0.25Recharge 3For 5 seconds, target foe is hexed with Wastrel's Demise. Each second while hexed, target foe and all foes adjacent to that foe take 1..10 damage and an additional 1..10 damage for each second this spell is in effect. This hex ends prematurely if target foe uses a skill. OQhjAwCMYQLBnAmO0lcATP2k3UAGear
Use the shared Mesmer gear page as the baseline.
Imperial Guard Reinforcement OrderCan help you survive a little more while sitting in the glitch spot as nothing can hit you except for 
Grenth's FingersGrenth's FingersDervish / Wind Prayers / Flash Enchantment SpellE 5Recharge 10All nearby foes are struck for 10..40 cold damage. For 30 seconds, your attacks deal cold damage. When this enchantment ends, you transfer 1..2 conditions to all nearby foes..
Titles
Norn5
Lightbringer0A high lightbringer title is not Required but do not forget to activate it at Chantry of secrets. Pick up quest rewards and bounties in DoA to quickly level it up.
Vanguard5Notes
- It is Required to understand how to move to the glitch spot (see video below).
- Do not take the room 5 quest in foundry, more information here.
- BackfireBackfireMesmer / Domination Magic / Hex SpellE 15Cast 3Recharge 20For 10 seconds, whenever target foe casts a Spell, that foe takes 35..140 damage. is powerful but expensive - use it on the Dervish lord in Veil, on Sus on the wall in City, on out of ball Dryders or Kis in foundry and on out of ball Heart tormentors in gloom.
- Avoid targeting warriors with your Energy SurgeEnergy SurgeElite / Mesmer / Domination Magic / SpellE 5Cast 2Recharge 15Target foe loses 1..10 Energy. For each point of Energy lost, that foe and all nearby foes take 9 damage. as they can run out of energy, reducing the damage.