Haste

Haste is a status effect that increases attack speed by 10% per level and increases mining speed by 20% per level. Negative levels decrease mining and attack speed, similar to Mining Fatigue. However, the attack speed increases are purely visual.

Immune mobs
All mobs are immune to Haste. Most mobs are unaffected by Haste as they cannot mine blocks.

Interaction with Mining Fatigue
Mining Fatigue III inflicted by elder guardians prevents the player from Instant breaking most blocks regardless of the Haste effect, along with a huge decrease of mining speed. However, lower levels of Mining Fatigue can be overcome by Haste of level III or greater, with a resultant reduced Haste effect.

Data values