D&D 5E Question on Spells (Fireball and Find Familiar, Bat)

[Sadras]

Something to ponder...or maybe not

Fireball
In our Next Campaign, our Mage casted Fireball within a confined underground complex, and since the full area of the Fireball was confined (walls, doors...etc) he argued that the Fireball would blossom further into the corridor expanding where it could.
The counter argument being that a Fireball exerts no 'force' upon its explosion, at least according to prior editions, so the rest of the players said this would stop the fireball from blossoming further. What say you?

Find Familiar, Bat
Later in the adventure our Mage summoned a Bat as his familiar. He sent the bat to search a darkened chamber ahead. The chamber in question was affected by a darkness spell that cancelled darkvision which the bat is listed as having since this is a magical being and not a natural one. The question is would you allow the bat to have echo-location like normal bats?

 

[Dausuul]

In our Next Campaign, our Mage casted Fireball within a confined underground complex, and since the full area of the Fireball was confined (walls, doors...etc) he argued that the Fireball would blossom further into the corridor expanding where it could.
The counter argument being that a Fireball exerts no 'force' upon its explosion, at least according to prior editions, so the rest of the players said this would stop the fireball from blossoming further. What say you?

By the rules as written, a fireball expands to the limit of its radius: 20 feet from the point of origin. Because fireball is a cloud rather than a sphere, that 20 feet can be measured around corners as well as in a straight line. However, you must be able to draw an unobstructed path no more than 20 feet long to the center-point.

For example, let's say you cast fireball targeting the center of a 20-by-20 room, where there is a door in the middle of the north wall (10 feet from the point of origin) connecting to an east-west corridor. An enemy standing in the corridor 5 feet from the door will get hit, because you can draw a 15-foot path from the enemy to the center-point (5 feet to the door, 10 feet from the door to the center). Another enemy standing 15 feet from the door will not get hit, because the shortest unobstructed path to the origin is 25 feet (15 feet to the door, 10 feet from the door to the center).



[SIZE=-2]Each square is 5 feet. The [/SIZE][SIZE=-2]fireball originates at the orange star. The red enemy will be hit by the blast, while the green enemy won't.[/SIZE]

This is the same way fireball was handled in 3E and 4E. In 1E and 2E, fireball had a fixed volume, which would shape itself as necessary with no set limit on radius. In a 10-foot-wide corridor with no side passages, a fireball would spread 165 feet in both directions from the origin! Next does not use this rule, but there's no reason you couldn't house-rule it this way if you wanted.

Later in the adventure our Mage summoned a Bat as his familiar. He sent the bat to search a darkened chamber ahead. The chamber in question was affected by a darkness spell that cancelled darkvision which the bat is listed as having since this is a magical being and not a natural one. The question is would you allow the bat to have echo-location like normal bats?

That's an interesting question. The bat's detection ability is described as "darkvision," and darkness specifically says it counteracts darkvision. On the other hand, the bat also has the special ability "cannot be blinded."

By a strict reading of the rules, darkness blocks the bat's "sight," because the bat is not being blinded per se--it's still able to see, just not through the enchanted area. However, I would probably house-rule that the bat's darkvision works normally because it isn't actually sight-based.

Edit: See Sage Genesis's post below. The bat familiar is supposed to have blindsight rather than darkvision. There don't seem to be any actual rules for blindsight in the playtest packet, but assuming it works the same way it did in 3E, it's unaffected by darkness of any kind.

 

[Sage Genesis]

Fireball
In our Next Campaign, our Mage casted Fireball within a confined underground complex, and since the full area of the Fireball was confined (walls, doors...etc) he argued that the Fireball would blossom further into the corridor expanding where it could.
The counter argument being that a Fireball exerts no 'force' upon its explosion, at least according to prior editions, so the rest of the players said this would stop the fireball from blossoming further. What say you?

In pre-3e editions a Fireball would fill up to its full "interior volume", which IIRC is ~33,000 cubic feet. So if you cast it in a confined space, it would indeed blossom out further than you'd expect.

This was not true in 3e, 4e, and now 5e/Next. Fireball is a 20' radius cloud. A "cloud" is a defined effect in the How To Play pdf and makes clear that the flames will go around obstacles, but still only out to its maximum radius. Fireball will not blossom further than 20'.

Find Familiar, Bat
Later in the adventure our Mage summoned a Bat as his familiar. He sent the bat to search a darkened chamber ahead. The chamber in question was affected by a darkness spell that cancelled darkvision which the bat is listed as having since this is a magical being and not a natural one. The question is would you allow the bat to have echo-location like normal bats?

The stats for the Bat under the Find Familiar spell are in error and should have been updated with the latest packet. The correct stats for the Bat can be found under the Druid wildshapes which make clear that it doesn't have darkvision but instead is has blindsight, which is unaffected by the Darkness spell.

 

[Sadras]

Thanks [MENTION=58197]Dausuul[/MENTION]. Can't XP thank-you, apparently I have to spread some love around.