As a DM, how do you handle this spell? Do you choose the animals or let the player choose?

The player has the choice of animals within the guidelines of the challenge rating. The examples they list are actually really good as I had a player use the Saber-Toothed Tiger plenty of times.

Quote from Retribune >>

The player has the choice of animals within the guidelines of the challenge rating. The examples they list are actually really good as I had a player use the Saber-Toothed Tiger plenty of times.

 What about the fact that the spell states the player only chooses the challenge rating? Did you read the article as of late?

Choose one of the following options for what appears:

• One beast of challenge rating 2 or lower

The spellcaster is choosing what to appearing, including the 'beast'. At no point does it imply that the GM decides, they only provide the stats.

Quote from b12n11w00t >>

Choose one of the following options for what appears:

• One beast of challenge rating 2 or lower

The spellcaster is choosing what to appearing, including the 'beast'. At no point does it imply that the GM decides, they only provide the stats.

 I agree

By default the DM chooses what actually shows up

This was handled in Sage Advice a while ago

Relevant text:

When you cast a spell like conjure woodland beings, does the spellcaster or the DM choose the creatures that are conjured? A number of spells in the game let you summon creatures. Conjure animals, conjure celestial, conjure minor elementals, and conjure woodland beings are just a few examples.

Some spells of this sort specify that the spellcaster chooses the creature conjured. For example, find familiar gives the caster a list of animals to choose from.

Other spells of this sort let the spellcaster choose from among several broad options. For example, conjure minor elementals offers four options. Here are the first two:

• One elemental of challenge rating 2 or lower
• Two elementals of challenge rating 1 or lower

The design intent for options like these is that the spellcaster chooses one of them, and then the DM decides what creatures appear that fit the chosen option. For example, if you pick the second option, the DM chooses the two elementals that have a challenge rating of 1 or lower.

A spellcaster can certainly express a preference for what creatures shows up, but it’s up to the DM to determine if they do. The DM will often choose creatures that are appropriate for the campaign and that will be fun to introduce in a scene.

Quote from b12n11w00t >>

Choose one of the following options for what appears:

• One beast of challenge rating 2 or lower

The spellcaster is choosing what to appearing, including the 'beast'. At no point does it imply that the GM decides, they only provide the stats.

 I agree.  If what Sage Advice indicates is accurate, and it was intended otherwise, they worded this spell so poorly.

I am new to playing a druid a I was wondering if it would be possible to also get wild shape animals out of this. Like If I cast this spell and a saber tooth tiger show up. Could I then wild shape into a saber tooth tiger

Don't know how you all handle this but a general rule of thumb for this at our table was half rounded up, the player gets to choose. Half rounded down the GM picks something that makes sense, we also ignore the "or lower" tag all agreeing that it's very dumb to spend a 3rd level spell to summon 1 crab CR0 (It says 1 beast CR2 or lower so technically you could summon a single beast with CR0 which is categorically stupid in combat). If you're pumping a 3rd level spell into this at level 5 and you have a specific beast you want, only to get something useless, then you'll never use this spell again which sucks because it's nearly a Core Druid spell, summoning is their gimmick, let them have it. That being said the party regularly gave me shit when I summoned the same beast a number of times, so I didn't abuse it as much as I know some people would and I rotated around using different beasts and different CR ranks. We tried dice rolls once to add some chaos to summoning, and I got a hunter shark in the middle of a desert, and it suffocated and died in a few rounds, and I died a little inside. I've heard another slightly different approach, when you first get this spell you must spend an hour in a ritual as part of your next long rest. THAT is when you contact nature and choose the 4 outcomes. You choose 1 outcome for each of the four categories and it can never be changed, if you choose giant boar for CR2 then any time you use this to summon CR2 beasts you only get giant boars regardless of the higher spell slots used. Not only that but you could even RP that these are now somehow your spirit fey animals and they know you and you know them, so give them names or something.

I wish this wasn't worded so poorly, in terms of who chooses the beasts.  From my searches, the vast majority of DM's let players choose the beast, because otherwise it would suck the usefulness and the sheer awesomeness out of the spell and playing experience.  But I don't like relying on DM's good will.  :)

   The way I like to handle this is to allow them to choose what to summon, but remove the option to summon 8 CR 1/4 creatures. Instead if they summon a creature that's lower than the CR level they can make, I give them 50% (rounded down) extra health and +1 to hit and damage (not giant owls, should be cr 1/2 anyway). That way you won't run into big groups of 8 wolves, giant owls, giant poisonous snakes, or swarms slowing your game down unless they cast at 5th level, at which point 8 creatures is.... annoying but fair. Instead you'd have something like 4 wolves with 16 health and 8 damage.
   If you want, make them choose a creature from the local environment, or a nearby one. If they want to summon 4 wolves in a city with a forest outside, have them make a check using their spell attack mod against a DC that gets higher the farther they are from the eviron they're calling from. If they fail the check, have choose a local creature for them. Oh you wanted 4 wolves in the middle of the city? Here's 4 swarms of rats, or horses or something.
   All told, this keeps things a little quicker, nerfs the strongest combat uses of this power a bit, and gives the players the freedom to plan around a specific creature, which is just fun. And if people really need 8 riding horses I'll allow it, but they lose the ability to attack.
   Some people say this spell is OP if you let them choose what to summon, but compare it to 5th level animate objects, where you can turn 10 coins, darts, ballbearings or whatever into 10 flying, 20 hp, +8 to hit, 8 (1d4+4) damage, AC 18 nuisances. 

Even if the DM picks the beasts after you select CR level, if you're using optional flanking rules, this is a wonderful way to gain advantage AND deal seriously stupid levels of damage.  Imagine you're critting on 19 + 20, and have elven accuracy...

Quote from ShaydyCharacter >>

   Some people say this spell is OP if you let them choose what to summon, but compare it to 5th level animate objects, where you can turn 10 coins, darts, ballbearings or whatever into 10 flying, 20 hp, +8 to hit, 8 (1d4+4) damage, AC 18 nuisances. 

~To be fair, one spell is gained a whole 4 levels earlier, and that's even more crucial if you're multiclassing.

If the DM chooses the beast then why is their the choice of "or lower" with each rating, then goes on to offer increased numbers for those lower ratings with the same "or lower" for each?This doesn't seem to square with the idea that the DM chooses the beast type. If a player only gets to choose the CR then why offer the "or lower" option if those lower ratings are already defined by increased numbers? The DM providing the stats seems to refer to rather appropriate beast for the setting, or because they are in fact fey spirits, and do not die like regular beasts, the only disappear (which they also do if you break concentration). I know what Sage Advice said, but even they seem to place the restrictions on what beasts may be appropriate for the area rather than a randomness inherent in the spell. My DM lets me choose, but they have to be from my regular beast shape list as determined by the druid tables in XGTE and what I have encountered in the game. Once again, the spell is limited by concentration, so that keeps it from being OP.

Just a reminder, Protection from Evil and Good used by the other side will force disadvantage on any summoned creatures' attacks as they are Fey spirits, presumably called from the Feywild, and not native beasts. Prepared with that, it's a relatively easy way to reduce Conjure spells' potency in battle, but does nothing to change the game play issues.

Bear in mind fellows-you can use a 9th level spell slot to summon 32 puppies.

Enjoy.

Quote from Shadowwolf0 >>

I am new to playing a druid a I was wondering if it would be possible to also get wild shape animals out of this. Like If I cast this spell and a saber tooth tiger show up. Could I then wild shape into a saber tooth tiger

 I would like to know as well. I would say yes as the fey would mimic the behaviour of the creature, but also no as it is not the actual best.

Thought?

Quote from TMoyer >>

If the DM chooses the beast then why is their the choice of "or lower" with each rating, then goes on to offer increased numbers for those lower ratings with the same "or lower" for each?This doesn't seem to square with the idea that the DM chooses the beast type. If a player only gets to choose the CR then why offer the "or lower" option if those lower ratings are already defined by increased numbers? The DM providing the stats seems to refer to rather appropriate beast for the setting, or because they are in fact fey spirits, and do not die like regular beasts, the only disappear (which they also do if you break concentration). I know what Sage Advice said, but even they seem to place the restrictions on what beasts may be appropriate for the area rather than a randomness inherent in the spell. My DM lets me choose, but they have to be from my regular beast shape list as determined by the druid tables in XGTE and what I have encountered in the game. Once again, the spell is limited by concentration, so that keeps it from being OP.

  Plus, what if you have a DM vs Players type that gives you a bunch of sea horses whenever you use the eight of 1/4 or lower?

That's when you find a new DM. ;)

Use 5th level spell slot, challenge rating 1/4, summon sixteen wolves.

With pack tactics your sixteen wolves will obliterate everything that stands in your way.

(except people that know fireball)