There are a couple exploits with Sneak / Embrace Shadows / shadow potions, but I don't recall this particular variation being mentioned before.
While hidden (at least for Sneak),
ranged magic attacks will not turn you visible.
A warrior can drink a shadow potion,
then stand near an opponent and use the spin attack to do damage without turning visible or triggering a counter-attack (right clicking on the ground, not an opponent).
Sneak can also be used to exploit a bug for extra speed.
As I recall, if you sneak, use a frog statuette, run around until your stamina drains, then transform back to human, you will keep the frog's speed. Using another statuette or possibly other actions would reset your speed, IIRC. The post in the old forum (no longer online) was titled 'SUper speed (for anyone who got bored of walking/running)'.
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