Staff of the Frost Hydra

Type	Weapon
Damage	100 (Summon)
Knockback	7.5 (Very strong)
Mana	20
Use time	30 (Average)
Velocity	14
Tooltip	Summons a sentry; Summons a powerful frost hydra to spit ice at your enemies
Rarity
Sell	20 GC
Research	1 required
Debuff	Frostbite(Desktop, Console and Mobile versions)
Debuff tooltip	It's either really hot or really cold. Either way it REALLY hurts
Chance	100%
Duration	5 seconds
Use
Summoned
Frost Blast
Frost Blast impact

This is the main page whose information applies to the Desktop, Console, and Mobile versions of Terraria.
For the differences of this information on Old-gen console and 3DS, see Legacy:Staff of the Frost Hydra.

Not to be confused with Frost Staff.

The Frost Hydra attacking two Mimics.

The Staff of the Frost Hydra is a Hardmode post-Plantera sentry summon weapon. It can summon the Frost Hydra sentry, which lasts for 10 minutes, remains stationary, and does not count against the player's minion capacity. The Frost Hydra will fire ice pellets at enemies within 60 tiles. It will automatically angle its head up and down, and turn left and right, to target enemies in any direction. Its projectiles can pierce twice, hitting up to 3 enemies, and applying a 15% damage penalty to the next hit for each enemy a projectile pierces, as well as inflict the Frostbite debuff.

The Frost Hydra can be summoned anywhere on the visible screen, even if blocks completely separate the player from the point clicked. It cannot, however, be summoned in the air, and will instead appear on the closest block or platform below the summoning point. The Staff of the Frost Hydra is always found in the Dungeon's Ice Chest, which can only be unlocked with a Frozen Key after Plantera has been defeated.

Its best modifier is Ruthless. The Mythical modifier provides the widest array of stat bonuses, but these primarily affect the initial summon rather than the resulting minion. Additionally, minions cannot deal critical hits. The only lasting advantage a Mythical Staff of the Frost Hydra has over a Ruthless one is knockback.

Notes

The Frost Hydra fires frost blasts at a rate of once per second.^[1]
The Frost Hydra does no contact damage to enemies. However, if a player contacts it in PvP, it will deal full damage and disappear.
Once cast, the player can switch to another weapon and the Frost Hydra will remain and still do damage.
The Frost Hydra provides a large burst of light on its initial appearance. Its projectile also produces moderate light.
The Frost Hydra can be summoned within solid blocks, which can be used to find ores and caves.
The Frost Hydra inflicts summon damage, so it will only benefit from minion damage bonuses. However, certain magic bonuses will affect the Staff's initial summoning (e.g. decreased mana use).
The Frost Blast applies 10 ticks of static immunity frames upon hitting an enemy. Due to the lack of local immunity frames summoning more than one will cause them to interfere with each other.
The Frost Hydra remains even if the player dies.

Tips

The high damage, versatile remote placement capability and lighting effect makes this Staff a valuable auxiliary weapon.
The remote capabilities of the Frost Hydra make it useful for battles and invasions, since it can be placed and left alone to slay enemies while the player does other things, such as making purchases, hiding, or fighting enemies in a different location.
The Frost Hydra will fall when blocks below it are removed, making it useful for guarding the player while digging vertical tunnels.
The Frost Hydra can also be useful in exploring caves as it can be summoned inside blocks and emits light.

Trivia

Despite being named after the Lernaean Hydra in Greek mythology, the Frost Hydra sentry only has one head.
The Frost Hydra measures approximately 4 tiles wide by 3 high and is semi-transparent.

History

Desktop version

Desktop 1.4.4.8: Projectile now uses static immunity frames instead of global.

Desktop 1.4.4:
- Projectile now inflicts Frostbite.
- Projectile speed increased by 50%.
- Now has a short delay on firing after being summoned.

Desktop 1.4.1:
- Projectile now pierces twice, hitting up to 3 enemies.
- Applies a 15% damage penalty to the next hit for each enemy a projectile pierces.