Thorn Damage
Thorns deal a percent of the enemy's max health in damage when they hit your tower (includes ranged attackers, 50% damage to boss)
Getting Thorns to specific milestones so it will take less hits to kill an enemy is the best tactics. Although, it seems Thorns need 1% more to reliably kill enemies, e.g. it takes 5 hits to kill an enemy with 25% thorns, while 26% takes it out in 4 hits.
| Hits to kill normal enemy | Thorns % | Enemy damage |
|---|---|---|
| 1 | 101% | 100% |
| 2 | 51% | 104% |
| 3 | 34% | 108% |
| 4 | 26% | 112% |
| 5 | 21% | 117% |
| 6 | 17% | 122% |
| 7 | 15% | 127% |
| 8 | 13% | 132% |
| 9 | 12% | 137% |
| 10 | 11% | 142% |
Thorns can be improved further beyond 100% using the Armor Modules substat that will allow to oneshot Enemies and 2-shot bosses. Thorns Damage Substat is available or Epic rariry and higher, but Rare is usually enough, since it gives 2% extra Thorns and you probably do not need more than that.
Workshop[edit | edit source]
Unlocked in the 
Workshop for 500 coins after Defense Percent and Defense Absolute. There are 99 upgrades that increase thorns by 1% each level for a maximum of 99% thorns (49.5% to bosses). Thorns damage does not trigger lifesteal. It is not necessary to receive damage to activate Thorns.
Protectors reduce thorn damage by 60% to all enemies in range.
| Level | Value | Cost | Total Cost |
|---|---|---|---|
| 1 | 1.00% | 60.00 | 0.00 |
| 2 | 2.00% | 85.00 | 145.00 |
| 3 | 3.00% | 117.00 | 262.00 |
| 4 | 4.00% | 157.00 | 419.00 |
| 5 | 5.00% | 206.00 | 625.00 |
| 6 | 6.00% | 264.00 | 889.00 |
| 7 | 7.00% | 331.00 | 1.22K |
| 8 | 8.00% | 409.00 | 1.63K |
| 9 | 9.00% | 497.00 | 2.13K |
| 10 | 10.00% | 596.00 | 2.72K |
| 11 | 11.00% | 706.00 | 3.43K |
| 12 | 12.00% | 828.00 | 4.26K |
| 13 | 13.00% | 961.00 | 5.22K |
| 14 | 14.00% | 1.11K | 6.32K |
| 15 | 15.00% | 1.26K | 7.59K |
| 16 | 16.00% | 1.43K | 9.02K |
| 17 | 17.00% | 1.62K | 10.63K |
| 18 | 18.00% | 1.81K | 12.44K |
| 19 | 19.00% | 2.02K | 14.46K |
| 20 | 20.00% | 2.24K | 16.70K |
| 21 | 21.00% | 2.47K | 19.17K |
| 22 | 22.00% | 2.72K | 21.89K |
| 23 | 23.00% | 2.98K | 24.87K |
| 24 | 24.00% | 3.26K | 28.13K |
| 25 | 25.00% | 3.54K | 31.67K |
| 26 | 26.00% | 3.85K | 35.51K |
| 27 | 27.00% | 4.16K | 39.67K |
| 28 | 28.00% | 4.49K | 44.17K |
| 29 | 29.00% | 4.84K | 49.01K |
| 30 | 30.00% | 5.20K | 54.20K |
| 31 | 31.00% | 5.57K | 59.77K |
| 32 | 32.00% | 5.96K | 65.73K |
| 33 | 33.00% | 6.36K | 72.10K |
| 34 | 34.00% | 6.78K | 78.88K |
| 35 | 35.00% | 7.22K | 86.09K |
| 36 | 36.00% | 7.66K | 93.76K |
| 37 | 37.00% | 8.13K | 101.89K |
| 38 | 38.00% | 8.61K | 110.49K |
| 39 | 39.00% | 9.10K | 119.59K |
| 40 | 40.00% | 9.61K | 129.21K |
| 41 | 41.00% | 10.14K | 139.34K |
| 42 | 42.00% | 10.68K | 150.02K |
| 43 | 43.00% | 11.24K | 161.26K |
| 44 | 44.00% | 11.81K | 173.07K |
| 45 | 45.00% | 12.40K | 185.46K |
| 46 | 46.00% | 13.00K | 198.47K |
| 47 | 47.00% | 13.62K | 212.09K |
| 48 | 48.00% | 14.26K | 226.35K |
| 49 | 49.00% | 14.92K | 241.27K |
| 50 | 50.00% | 15.59K | 256.85K |
| 51 | 51.00% | 16.76K | 273.61K |
| 52 | 52.00% | 17.48K | 291.10K |
| 53 | 53.00% | 18.22K | 309.32K |
| 54 | 54.00% | 18.98K | 328.30K |
| 55 | 55.00% | 19.76K | 348.06K |
| 56 | 56.00% | 20.55K | 368.62K |
| 57 | 57.00% | 21.36K | 389.98K |
| 58 | 58.00% | 22.19K | 412.17K |
| 59 | 59.00% | 23.04K | 435.20K |
| 60 | 60.00% | 23.90K | 459.10K |
| 61 | 61.00% | 24.78K | 483.88K |
| 62 | 62.00% | 25.68K | 509.56K |
| 63 | 63.00% | 26.59K | 536.15K |
| 64 | 64.00% | 27.53K | 563.68K |
| 65 | 65.00% | 28.48K | 592.16K |
| 66 | 66.00% | 29.45K | 621.61K |
| 67 | 67.00% | 30.44K | 652.05K |
| 68 | 68.00% | 31.44K | 683.49K |
| 69 | 69.00% | 32.47K | 715.96K |
| 70 | 70.00% | 33.51K | 749.47K |
| 71 | 71.00% | 34.57K | 784.05K |
| 72 | 72.00% | 35.65K | 819.70K |
| 73 | 73.00% | 36.75K | 856.45K |
| 74 | 74.00% | 37.87K | 894.32K |
| 75 | 75.00% | 39.00K | 933.32K |
| 76 | 76.00% | 42.16K | 975.48K |
| 77 | 77.00% | 43.39K | 1.02M |
| 78 | 78.00% | 44.64K | 1.06M |
| 79 | 79.00% | 45.92K | 1.11M |
| 80 | 80.00% | 47.21K | 1.16M |
| 81 | 81.00% | 48.52K | 1.21M |
| 82 | 82.00% | 49.85K | 1.26M |
| 83 | 83.00% | 51.19K | 1.31M |
| 84 | 84.00% | 52.57K | 1.36M |
| 85 | 85.00% | 53.95K | 1.41M |
| 86 | 86.00% | 55.37K | 1.47M |
| 87 | 87.00% | 56.79K | 1.52M |
| 88 | 88.00% | 58.25K | 1.58M |
| 89 | 89.00% | 59.72K | 1.64M |
| 90 | 90.00% | 61.21K | 1.70M |
| 91 | 91.00% | 62.72K | 1.77M |
| 92 | 92.00% | 64.25K | 1.83M |
| 93 | 93.00% | 65.80K | 1.90M |
| 94 | 94.00% | 67.38K | 1.96M |
| 95 | 95.00% | 68.97K | 2.03M |
| 96 | 96.00% | 70.59K | 2.10M |
| 97 | 97.00% | 72.22K | 2.18M |
| 98 | 98.00% | 73.88K | 2.25M |
| 99 | 99.00% | 75.55K | 2.33M |
Lab[edit | edit source]
Thorns do not have their own lab, but Garlic thorns increase their efficiency against the Vampire enemies.
Garlic Thorns[edit | edit source]
Lab Research Unlocks at Tier 2 Wave 1000. There are 10 upgrades. The lab causes Vampire elite enemies to take a % of your thorns damage per second while using its ranged attack.
| Level | Time | Cost | Value |
|---|---|---|---|
| 1 | 1d 3h 13m | 4,500 | 0.5 |
| 2 | 1d 6h 5m | 7,100 | 1.0 |
| 3 | 1d 9h 49m | 13,300 | 1.5 |
| 4 | 1d 14h 59m | 26,700 | 2.0 |
| 5 | 1d 22h 5m | 50,900 | 2.5 |
| 6 | 2d 7h 33m | 89,500 | 3.0 |
| 7 | 2d 19h 45m | 146,100 | 3.5 |
| 8 | 3d 11h 5m | 224,300 | 4.0 |
| 9 | 4d 5h 54m | 327,700 | 4.5 |
| 10 | 5d 4h 32m | 459,900 | 5.0 |