Strength

Strength is an effect which increases attack power.

Effect
Increases melee damage by × level $$. Negative levels decrease melee damage, with attacks being ignored entirely if damage would be 0 or lower.

$$, melee damage under the Strength effect can be found through the equation $$BaseDamage\times1.3^{level}+{1.3^{level}-1\over0.3}$$, where $$BaseDamage$$ is the default damage of whatever weapon or tool is used to attack.

Immune mobs
Withers and ender dragons are immune to Strength. While not immune, any mobs that cannot attack are unaffected by Strength.

ID