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 effect strength level x can be found by the recursive formula where  at   is the base attack damage with whatever weapon or tool is used to attack, and   is rounded down to the nearest integer with each recursion.

meaning round down.

Immune mobs
Boss mobs are immune to strength. While not immune, any mobs that cannot attack are unaffected by Strength.

ID