Life Steal

Your attacks have a x% chance to heal you for 1 HP per hit. Each time you life steal 1 HP, you cannot life steal again for 0.1 second. Meaning the maximum possible life gained per second is 10. This means that high percentages of life steal have diminishing returns, as the chances of multiple instances of life stealing happening within the same 0.1 second drastically increases.

Extra projectiles, pellets, pierces and bounces trigger lifesteal.

But if those hits connect within the 0.1 second time window, it means you are limited to healing 1 hp.

If this is negative it acts like the stat is 0.

Explosions do not trigger life steal.

Weapons in the Medical class have innate Life Steal, and the Blade weapon class have Life Steal bonuses.

Strategy

Life Steal is heavily dependant on your Attack Speed and a Weapon's cooldown. Weapons that attack quickly (such as SMG) will proc far more often than a slower weapon.

Vs. HP Regeneration

Compared to HP Regeneration:

Life Steal can potentially offer much faster healing for less overall materials spent, by using weapons with fast cooldowns, Medical weapons, and a decent investment into Attack Speed.
However, HP Regeneration is more reliable than Life Steal. It doesn't depend on your weapon speed, always procs, and it doesn't require you to hit anything. Especially melee users can get in trouble if they are put on low HP, and are forced to leave the melee range to flee. In this case, life steal stops healing you.
Life Steal's cap of 10 HP/second means it has a hard limit on its healing capabilities, even at 100%. However, HP Regeneration takes over 100 to heal past 10HP/sec (see here), so this difference isn't noteworthy unless you're investing heavily into the stat.

Items

Positive

These items increase your Life Steal.

Due to Item Tags, the Character(s) Lich, Masochist, Sick, Vampire have a higher chance to find these items in the Shop.

Name	Rarity	Effects	Base Price	Limit	Unlocked By
Bat	Tier 1	+2 % Life Steal -2 Harvesting	20
Blood Leech	Tier 2	+2 % Life Steal +2 HP Regeneration -3 Harvesting	45
Butterfly	Tier 1	+2 % Life Steal -1 Elemental Damage	30
Cape	Tier 4	+5 % Life Steal +20 % Dodge -2 Melee Damage -2 Ranged Damage -2 Elemental Damage	110
Fin	Tier 3	+10 % Speed +3 % Life Steal -8 Luck	65		Win a run with Speedy
Mouse	Tier 3	+5 % Life Steal +10% Enemies -5 Harvesting	55	5
Octopus	Tier 4	+12 Max HP +5 HP Regeneration +3 % Life Steal -8 % Crit Chance	105		Win a run with Mutant
Ritual	Tier 2	+6 % Damage +2 % Life Steal -2 Engineering	60		Win a run with Ghost
Whetstone	Tier 2	+4 % Life Steal -3 Knockback	40		Win a run with Sick

Negative

These items decrease your Life Steal.

Name	Rarity	Effects	Base Price	Limit	Unlocked By
Baby Gecko	Tier 1	+10 Range +25% chance to instantly attract a material when it’s dropped	18	4
Banner	Tier 2	+20 Range +10 % Attack Speed -5 Knockback	55
Bean Teacher	Tier 3	+50 % XP Gain -2 % Life Steal	70
Clover	Tier 3	+20 Luck +6 % Dodge -2 % Life Steal	65
Exoskeleton	Tier 4	+3 Armor +5 % Crit Chance +5 Engineering +5 % Speed -2 HP Regeneration -2 % Life Steal	90
Plant	Tier 1	+3 HP Regeneration -1 % Life Steal	15
Robot Arm	Tier 4	+3 Melee Damage at the end of a wave +3 Engineering at the end of a wave -1 Max HP at the end of a wave	100		Win a run with Engineer

Characters

These Characters start with different Life Steal, or have mechanics related to Life Steal:

Name	Stats	Unlocked By	Unlocks	Item Tags
Chunky	Max HP modifications are increased by 25% +1% Damage for every 3 Max HP you have +3 HP recovered from consumables -100% Life Steal HP Regeneration modifications are reduced by 50% Dodge modifications are reduced by 50% Speed modifications are reduced by 100%	Die for the first time	Potato Thrower	Max HP, Luck
Wildling	+30% Life Steal with Primitive weapons You start with 1 Stick You can't equip weapons above tier 2	Kill 10000 enemies	Hatchet	None
Sick	+12 Max HP +25% Life Steal You take 1 damage per second (does not give invulnerability time) -100 HP Regeneration	Reach -5 % HP Regeneration	Whetstone	Life Steal

Weapons

These Weapons affect Life Steal:

Name	Class	Damage	Attack Speed	DPS	Crit Damage/Chance	Range	Knockback	Lifesteal	Base price	Unlocked by
Medical Gun	Medical, Gun	10(100%) 15(100%) 20(100%) 30(100%)	0.87s 0.77s 0.65s 0.53s	11.5(115%)/s 19.5(130%)/s 30.8(154%)/s 56.6(189%)/s	x2 (3%) x2 (3%) x2 (3%) x2 (3%)	400 400 400 400	0 0 0 0	40% 45% 50% 60%	15 31 61 122	Default
Scissors	Medical, Precise	5(80%) 10(80%) 15(80%) 20(80%)	1.01s 0.98s 0.94s 0.86s	5.0(79%)/s 10.2(81%)/s 16.0(85%)/s 23.3(93%)/s	x2 (10%) x2.15 (12%) x2.3 (15%) x2.5 (20%)	150 150 150 150	2 2 2 2	40% 45% 50% 60%	15 31 61 122	Default
Circular Saw	Blade, Medical	- 10(100%) 15(100%) 25(100%)	- 0.72s 0.67s 0.62s	- 13.9(138%)/s 22.4(149%)/s 40.3(161%)/s	- x2 (5%) x2 (10%) x2 (20%)	- 175 175 175	- 0 0 0	- 45% 50% 60%	- 46 86 173	Default

Weapon Classes

These Weapon Classes affect Life Steal:

Class	Bonuses	Weapons
Blade	(2)+1 Melee Damage 1% Life Steal (3)+2 Melee Damage 2% Life Steal (4)+3 Melee Damage 3% Life Steal (5)+4 Melee Damage 4% Life Steal (6)+5 Melee Damage 5% Life Steal	Chopper Circular Saw Sword Captain's Sword Chainsaw Thunder Sword Excalibur