Updated for Town Hall 18 (October 2026).
The Poison Spell is the go-to answer for defending Clan Castle troops: it leaves a 4-tile toxic cloud for 16 seconds that damages, slows and weakens enemy units but never touches buildings. It is the first Dark spell, unlocked as soon as you build the Dark Spell Factory at Town Hall 8, and it takes 1 housing space. The current max is level 12 at Town Hall 18.
How the Poison Spell works
Poison hits every defending unit in its cloud, ground or air: Clan Castle troops, defending heroes, and Skeletons from a Skeleton Trap. Each one gets three effects at once.
- Damage that starts low and climbs the longer the unit stays poisoned, a bit like a single-target Inferno Tower. Heroes take much less of this damage than troops do.
- Slower movement.
- A slower attack rate, which is the big one. At max level, a poisoned troop’s attack rate drops by 74%.
The poison keeps working for 6 seconds after a unit walks out of the cloud. Idle defending troops (not heroes) try to step out of it, so it works best while they are busy fighting your army. Miners that are underground are not affected.
Two Poisons on the same spot ramp up faster but do not raise the damage cap, so stacking several at once mostly wastes spells.
Poison Spell levels
Poison is researched in the Laboratory with Dark Elixir. Costs and times are standard values before a Gold Pass discount. Damage is the peak damage per second once the ramp is complete.
| Level | Max damage per second | Speed reduction | Attack rate reduction | Research cost (Dark Elixir) | Research time | Lab level | Town Hall needed |
|---|---|---|---|---|---|---|---|
| 1 | 90 | 26% | 35% | None | None | None | 8 |
| 2 | 115 | 30% | 40% | 5,000 | 6h | 6 | 8 |
| 3 | 145 | 34% | 45% | 10,000 | 18h | 7 | 9 |
| 4 | 180 | 38% | 50% | 21,500 | 2d | 8 | 10 |
| 5 | 220 | 40% | 55% | 35,000 | 3d | 9 | 11 |
| 6 | 260 | 42% | 60% | 55,000 | 4d | 10 | 12 |
| 7 | 280 | 44% | 65% | 77,500 | 5d | 11 | 13 |
| 8 | 300 | 46% | 68% | 100,000 | 6d 12h | 12 | 14 |
| 9 | 320 | 48% | 70% | 135,000 | 7d | 13 | 15 |
| 10 | 340 | 50% | 72% | 175,000 | 8d | 14 | 16 |
| 11 | 360 | 51% | 73% | 230,000 | 9d 16h | 15 | 17 |
| 12 | 380 | 52% | 74% | 350,000 | 14d 12h | 16 | 18 |
Poison gets a new level at every Town Hall from 9 to 18, so a Town Hall 18 Poison is a lot stronger than the one most Town Hall 12 players carry.
How to use the Poison Spell
Pull the Clan Castle first
Send one or two cheap troops at the edge of the Clan Castle trigger radius to draw the defenders out to a corner. Once they are fighting your bait, drop the Poison right on the group and add Wizards or a handful of Archers to finish them while they are slowed. Defenders that are busy attacking stay in the cloud; if your bait dies too early, they wander out.
What it kills on its own
Even a low-level Poison wipes out Wizards, Witches, Minions, Skeletons and the early Barracks troops. Heavy units such as Dragons, Electro Dragons, Golems and P.E.K.K.As usually survive one spell, but the attack-rate cut makes them far less dangerous while your army finishes them. High-hitpoint units like Balloons, Baby Dragons and Valkyries take the most from the damage ramp.
Best pairings
A Freeze Spell on top of a Poison pins the defenders inside the cloud so the damage can climb. Poison is also the cleanest answer to Skeleton Trap Skeletons: trigger the trap with a throwaway troop, then cover the spawn. Against defending heroes it is mainly a slow, since heroes resist the damage; a Freeze that also catches a nearby defense is a fair alternative.
Compared with the Lightning Spell, which also uses 1 space, Poison deals more total damage to troops and slows them, but Lightning can hit buildings and lands instantly.
”"Give your army the upper hand against enemy troops with this deadly poison! Defending units that linger in a Poison Spell's toxic cloud will move slower, attack slower and take damage with increasing severity over time. Poison Spells do not affect structures."
How to defend against Poison
- Fill your Clan Castle with troops that still hit hard while slowed: an Inferno Dragon, whose beam still reaches very high damage, or Baby Dragons and Valkyries.
- Ice Golems are a good choice because their freeze on death works the same with or without poison.
- Set a defending hero’s trigger area at or just behind the Clan Castle’s, so the attacker has to deal with both at once and may need a second Poison.
- Spread out your Skeleton Traps so one Poison can’t clear Skeletons from several traps.
Recent changes
- June 27, 2022: no longer costs Dark Elixir to brew.
- October 10, 2022: level 9 added; poison no longer hits Miners while they are underground.
- December 12, 2023: level 10 added.
- February 10, 2025: level 11 added.
- March 2025, “Clash Anytime” update: brewing time removed.
- November 2025, Town Hall 18 update: level 12 added; level 11 research cut to 230,000 Dark Elixir and 9 days 16 hours.
- February 23, 2026: Poison began affecting the Town Hall 18 Guardians, with a reduced slow.
- April 27, 2026: Guardian poison damage set to 30% of normal.
Defenders can use the same effect: the Spell Tower has a Poison mode that hits attacking troops.
Poison Spell FAQ
Does Poison damage buildings?
No. It only affects defending units: Clan Castle troops, heroes, Skeletons and, at reduced strength, Guardians.
How long does the Poison Spell last?
The cloud lasts 16 seconds, and units stay poisoned for 6 seconds after leaving it.
Does Poison work on Guardians?
Yes, since February 2026, but at reduced strength. Since April 27, 2026 it deals 30% of its normal damage to them.
What Town Hall unlocks Poison?
Town Hall 8, the level where you can build the Dark Spell Factory.
Sources: Supercell release notes (February 2026 update, Sound of Clash update, April 2026, Clash Anytime update), in-game data.
