Knockback

Knockback is a basic mechanism in Terraria, whereby players and enemies are repelled in the opposite direction of an attack. Most weapons and environment objects that cause damage also cause knockback, to varying degrees. Some enemies are immune to knockback, particularly Bosses and other enemies that travel through blocks, like Worms and Man Eater. Some enemies also have varying degrees of knockback resistance.

Equipping most Shields will grant the player knockback immunity.

The most player-inflicted knockback comes from the Slap Hand, which has a knockback value of 20. This is followed immediately by the Golem Fist with a knockback value of 12, and the Thorns Potion, which retaliates with 10 knockback when its effect triggers.

Knockback is capped at 16 (22.4 if it is a Critical hit). This cap is applied after calculating the enemy's knockback resistance.

Various modifiers, and the Titan Glove accessory, can increase player-inflicted knockback.

Immune enemies
Other:
 * All Bosses except Brain of Cthulhu in its second phase, and Golem's Fists.
 * All Plants except Angry Trapper
 * All Worms (Not including the critter Worm)
 * Antlion
 * Blazing Wheel
 * Dungeon Guardian
 * Lihzahrd (2nd form)
 * Paladin
 * Pirate Captain
 * Spike Ball
 * Headless Horseman
 * Gray Grunt
 * Lunatic Devote