# If an area is covered in both Ball Bearings and Caltrops, does the creature need to move at half speed or quarter speed to avoid both their effects?

So say I drop both Caltrops and Ball Bearings onto the same area. If a creature, for example an orc, moves across the area and doesn't wish to make any saves, does it move at half or quarter speed?

• If that is OP's assumption, they should make it clear in the body of the question (which basically matches the new title). While the original title might imply that assumption, it's not clear whether that's the case. @Jayjaxx, could you clarify? Commented Feb 19, 2019 at 1:51
• The old title ("Do the Ball Bearings and Caltrops stack in regards to speed?") was just ambiguous. The new title is precise and an improvement. It doesn't affect the accuracy of either answer and neither title conveys a different intent for the querent. Commented Feb 19, 2019 at 1:53

# The creature can move at half speed to avoid both effects.

Neither ball bearings nor caltrops state that a creature's speed is physically penalized, just that a creature can choose to move at half speed to avoid their effects. Then we can handle each consideration separately.

First, ball bearings (emphasis mine):

As an action, you can spill these tiny metal balls from their pouch to cover a level, square area that is 10 feet on a side. A creature moving across the covered area must succeed on a DC 10 Dexterity saving throw or fall prone. A creature moving through the area at half speed doesn't need to make the save.

Is the creature moving through the area of ball bearings at half speed? Then they are unaffected.

Next, caltrops (emphasis mine):

As an action, you can spread a bag of caltrops to cover a square area that is 5 feet on a side. Any creature that enters the area must succeed on a DC 15 Dexterity saving throw or stop moving this turn and take 1 piercing damage. Taking this damage reduces the creature's walking speed by 10 feet until the creature regains at least 1 hit point. A creature moving through the area at half speed doesn't need to make the save.

Is the creature moving through the area of caltrops at half speed? Then they are unaffected.

An area covered in both ball bearings and caltrops is no different. Is the creature moving through the area at half speed? Then they are unaffected.

Note that if the creature chose to move greater than half their speed across the combined area then they would be forced to make both saving throws, one against the ball bearings and one against the caltrops, possibly suffering one effect or the other effect or both effects combined.

• Comments on RPG.SE are for suggesting actionable improvements to a question or answer. I don't see any suggestions. If you have suggestions, please let me know explicitly. Otherwise, please be advised that chatty comments will be flagged for deletion, but you can show your support/opposition to my answer by upvoting/downvoting instead. Thanks. Commented Feb 19, 2019 at 17:36
• Would this also fall under the "you cannot double up effects" general rule? Similar to how you cannot stack advantage or other effects? Commented Feb 19, 2019 at 22:13
• No, because there is no effect to double. The character is not under any effect. The character can choose to do a thing that meets two independent requirements. Commented Feb 19, 2019 at 22:14

# No, moving at "half speed" is enough to avoid both Dex saves

The description of ball bearings states:

As an action, you can spill these tiny metal balls from their pouch to cover a level, square area that is 10 feet on a side. A creature moving across the covered area must succeed on a DC 10 Dexterity saving throw or fall prone. A creature moving through the area at half speed doesn't need to make the save.

And the description of caltrops says:

As an action, you can spread a bag of caltrops to cover a square area that is 5 feet on a side. Any creature that enters the area must succeed on a DC 15 Dexterity saving throw or stop moving this turn and take 1 piercing damage. Taking this damage reduces the creature's walking speed by 10 feet until the creature regains at least 1 hit point. A creature moving through the area at half speed doesn't need to make the save.

If a creature moving through the area moves at half speed, then it meets the (identical) condition for both items, and avoids the need to make a Dex save.

If the creature doesn't move at half speed, and enters a square filled with both ball bearings and caltrops, the creature is forced to make 2 Dex saves: a DC 10 Dex save to avoid falling prone, and a DC 15 Dex save to avoid taking 1 piercing damage and being prevented from moving further this turn (and having its walking speed reduced).