Wearing a ring of free action gives you the free action extrinsic, which protects you from paralysis.
This immunity includes protection from:
- Paralysis container traps
- A thrown or quaffed potion of paralysis or potion of sleeping
- Paralysis or stunning spells (reduced to one turn)
In addition, protection from the paralyzing attacks of the following monsters:
- Floating eyes ("You momentarily stiffen under the floating eye's gaze!)
- Gelatinous cubes
- Ghouls
- Guardian nagas
- Shades
- Yeenoghu
Free action does not:
- Protect you from being "paralyzed" by fear when an enormous ghost appears in a deserted temple, or you chat to a skeleton
- Protect you from fainting due to hunger
- Protect you from sleep, except from potions of sleeping
- Protect you from stunning, except from spells
- Protect you from any grabbing attacks, including drowning
- Protect you from bear traps, pits, spider webs, or any physically binding traps
- Protect you from stoning
- Allow you to move freely on the Plane of Air or Plane of Water
- Prevent you from being incapacitated by lightning in clouds on the Plane of Air
- Grant any extra turns
Identifying a ring of free action is straightforward in theory, but difficult in practice. Just wear the ring and allow yourself to be hit by one of the attacks against which free action protects. Since these attacks are rare (but often lethal), identifying a ring of free action in this way is uncommon. Perhaps the safest means of use-identifying a ring suspected to be free action is to drink a potion of paralysis while locked in a closet standing on a permanent Elbereth, however this method consumes a potentially valuable potion. A more dangerous but less expensive way is to melee a gelatinous cube in an otherwise cleared level while standing on Elbereth.
Eating the ring will give you intrinsic sleep resistance instead of free action.
In SLASH'EM, the ring does protect against grabbing attacks, including those of both drowning monsters and mind flayers, with a chance dependent on your Luck - 50% at 0 Luck, 90% when maxed out. It gives the message "<foo> grabs you, but you quickly free yourself!"
Dropping a ring of free action into a sink produces the message, "You see the ring slide right down the drain!"
