Staff of Haste

The magical bolt from this staff will temporarily double the speed of any monster it hits. This can be counterproductive against enemies but can prove useful when aimed at your allies. Unfortunately, you cannot use this or any staff on yourself.

While counterproductive to use on enemies, a staff of haste works well with strong allies. The duration of the haste is 2 + (4 * the enchantment level of the staff). 

The description of this staff can be misleading, as it simply means that you cannot use the staff directly on yourself. Like all staves, though, the bolt from the staff of haste can be reflected, potentially allowing the player to apply the effect to themselves in situations where they have reflective targets, such as the Warden of Yendor, a summoned Guardian, etc.