Quote from Horderndnd >>

What happens if you enlarge a create that can swallow another creature? Can it now swallow larger creatures?

 what if you enlarge a creature that has been swallowed

This keeps saying "target" and "creatures" does this mean humanoids? Humans, dwarves, elves, etc? Or is it literally just creatures 

Quote from Enderstine >>

Quote from nessi_c >>

I'm a little confused because this isn't tagged as a bard spell, but books and independent sites (roll20, dnd5e.*******) list it as a bard's spell.
Is there a reason it has been removed?

 That's what I've been wondering. I was looking around at other sources about bard spells (since i can't see some of them without having to buy a digital book), when i noticed that in dnd5e that it's a spell that a bard can use, but not in DnD Beyond. Perhaps it was overlooked or something?

 Bit late, but had this issue when looking into this. It got added in Tasha's but it isn't on the Bard spell list in the PHB. If you want to add it in DndBeyond you can copy the spell as Homebrew and add it to the Dard and Druid lists.

So let’s say I have a pretty little duergar rune knight, who happens to use giant's might right before they want to use enlarge. Which should be possible I believe. That means the character should go from medium to large and from large to gargantuan right? Since the spell specifically tells us that the target's size doubles in all dimensions. So the target (my pc) should double from a 2 x 2 size to a 4 x 4 size? But then it says it grows only one category? I assume the latter thing is what’s intended, but what’s the first sentence for then? 

To stomp on them, crush them, throw them against a wall.

So, uh-

A ring wouldn't work, but I think a bracelet might

ever since they added Fairies, i have a homebrew that the effect can be permanent when used on an object (and only objects, if cast on a person at higher levels then the effect lasts longer up to 9hrs, 1hr per level cast) if cast at higher levels....so that Fairy (and other small/tiny) PCs can buy stuff then shrink it to their size or shrink loot they find so they can use it.

Okay, so does the target doubles its size or just enlarges to the next size category?
Would Large horse 2x2 squares become Huge 3x3 or 4x4?

Roll20 uses not PHB or Basic Rules, but SRD 5.1 document, so that spell was basically bards' and is not anymore, except you use SRD as a main source of rules.

Put an enlarged ring around the neck of a dragon as a gift of goodwill

A sneaky wizard has the dispel magic spell at the ready

You see where this is going

This is what I call the Ring of Righteousness tm.

Enjoy

This spell has been added to bards via Tasha's Cauldron of Everything.

Someone please update this.

Quote from Tuomari >>

Roll20 uses not PHB or Basic Rules, but SRD 5.1 document, so that spell was basically bards' and is not anymore, except you use SRD as a main source of rules.

The number of spaces taken up (or "controlled") is not what doubles. (Or halves) The number of spaces taken up is determined by the creature's size category. The size category is roughly related to the creature's dimensional size, but this relationship is not clearly delineated in the rules. It can be roughly extrapolated based on information given about creatures of various size categories in various sources. (i.e. Hill Giants are noted to be around 16-17 ft. tall and are considered Huge)

The creature's actual dimensions are what double. Consider a human who is 6 ft. tall. They would also be somewhere around 16" wide (at the shoulders), and maybe 8" deep (chest/head). I am kind of extrapolating here, but you get the gist. Those are the dimensions that get doubled. The Enlarged human would then be 12 ft. tall, with 23" shoulders and a 16" deep chest/head. That size range generally equates to a Large creature, which takes up a 2x2 area.

A 10 ft. tall ogre, on the other hand, would double in size to 20 ft., which is firmly in Huge territory, so it goes from a 2x2 area to a 3x3 area. It's height doubles, but not its area of control on the battlefield.

Well now there is the path of the giant barbarian and at level 14 with enlarge he can become gargantuan

Can it be cast on the caster or does "any creature you can see" negate that?

Quote from Magical_Mr_Mantle_ >>

Put an enlarged ring around the neck of a dragon as a gift of goodwill

A sneaky wizard has the dispel magic spell at the ready

You see where this is going

This is what I call the Ring of Righteousness tm.

Enjoy

Enlarging only doubles the size. 

Can you cast this on yourself?

Quote from Sixlooter >>

My question here is, if this isn't the ultimate door/gate opener with reduce. Reduce a door and just kick it away. As there is no limit to object size, you could even win a siege with this by shrinking the giant closed dwarven stone portal by one size, making it just a rock that does not really hinder anyone anymore.

Even better for doors that have traps or are magically warded, because you do not open them anymore but merely step over or around them...

I guess I would give certain structures some kind of saving throw, especially enchanted doors and gates, but if you just use what is written there, it is a mega powerfull spell.

Quote from Pancakeli >>

Or you could have several casters using the same spell on one target. So far as I know there is no rule in any book that says "A target cannot be under the effects of the same spell cast by multiple creatures." So if you had 2 people reduce one target than suddenly the target is a quarter their original size and a sixty-fourth their original weight or inversely 4 times as large and 64 times heavier. 
If you got 3 casters with Enlarge/reduce suddenly you have a (presumably originally medium) barbarian who is as large as the Tarrasque.
You could go 1 level of rogue for expertise in athletics, maybe pick up the grappler feat, and now you can have a nearly fair WWE match with dnd's very own Godzilla. 
EDIT:  So unfortunately after some reading of some rules, a target cannot be under the effects of the same spell multiple times, so unfortunately there can be no gargantuan barbarian wrestling match without some breaking of the laws of reality  :( (otherwise known as homebrew ;) )

 In theory a rune knight fighter could become huge with the combination of Giant's Might (which makes medium or smaller creatures large) then using enlarge to grow an extra size, additionally as a goliath the Powerful build could help with grappling the Tarrasque.

Unless it's a Mount through Find Steed/Find Greater Steed! Then casting Enlarge on yourself will also enlarge your mount!

If a Circle of the Moon Druid wild shapes into a Giant Constrictor Snake, then is Enlarged by some friendly Wizard, Sorcerer, or Artificer, then its size category would graduate from Huge to Gargantuan. Under homebrew, wouldn't the Gargantuan Constrictor Snake gain the Purple Worm's "Swallow" ability?