Zapping a wand of polymorph at Master skill gives you control over the form the target monsters polymorph into, whether that is yourself or others. Other monsters still get their chance to resist the polymorph entirely.

It would not give you control over what an object would polymorph into, for obvious reasons.

However, if there are monsters that can use the wand of polymorph at master skill, this has the potential to become very annoying very fast, since they would be able to turn the player into a sessile monster, make them break their armor, or turn themselves into something very threatening and out of depth.

For variants with wand skill, higher wand skill improves the outcomes from snapping a wand. Ideas include increasing the effective number of remaining charges, increasing the explosion radius, and decreasing the damage the player takes.

Higher wand skill makes the shooter’s wand rays harder to dodge.