I want it so I can teleport characters to the top of a tower in D&D 5e. They will then battle their way down the tower. My idea is that they touch an object and it teleports them there. Is this a thing, or is there a better way of doing this?

I want to use this for an idea I have for a 1 off adventure: the party is told that farm animals are going missing. They find out it's from a teleport masked as an item (I haven’t decided what item). They use the item to teleport to where they are going, find they are food for a tower of orcs. They fight the orcs and face a wizard at the end who made the teleport item.

Short Answer: Yes, you can.

I'm not familiar with the D&D5 rules in particular, but even if there wouldn't be any mention of a teleporting item or spell, nothing prevents you as a GM from making it up for your table or specific campaign.

The same goes for any limitations on existing items. If it doesn't exactly work the way you need by the rules, you can just houserule it to do so.

Glyph of Warding

Have an NPC wizard cast glyph of warding, along with teleportation circle spell as the stored spell, declaring the top of the tower as your destination. Specify your trigger "when a creature touch this glyph/object".

Of course, PC can also do this.

Note: You can use teleport instead of teleportation circle, but teleportation circle is far superior.

• 
  teleport requires the triggering creature to be "willing". Your DM may rule that the triggering creature is not willing, thus wasting your spell.


• 
  teleport can only target the triggering creature, because the glyph of warding requires the stored spell to target a single creature or an area.


• 
  teleport is a 7th level spell, while teleportation circle is a 5th level one. You have access to teleportation circle earlier, and will only need 5th level spell slot instead of 7th.


• 
  teleport has a chance to fail, even when teleporting to a permanent magic circle. If you need a reliable method, teleportation circle is better.

Some also argues that teleportation circle is not a valid spell for glyph of warding, you can learn more about that from this question: Glyph of Warding and Teleportation Circle

Yes, you can absolutely do this

As others have mentioned there is significant GM Fiat to create such creations in D&D 5e.

Note: the rest of this answer contains spoilers for a portion of a published adventure.

You might want to take some inspiration from the adventure

Waterdeep: Dungeon of the Mad Mage.

In that adventure:

On level 15 (p. 194), the concept of a Teleport Trap is introduced that has the following effect:

A creature that enters the trap’s space is teleported along with any objects it is wearing or carrying to another teleport trap (or the nearest unoccupied space). There is no saving throw to resist the teleportation effect, and the destination varies from trap to trap. Once a creature has been teleported in this way, it is unaffected by teleport traps on this level for 1 hour.



When a creature is teleported by a trap, Halaster’s booming voice shouts “Teleported!” in Common. The magical voice originates at the point of departure and the point of arrival, and it is audible in both locations out to a range of 100 feet.



Some teleport traps have additional effects, as described in their encounter locations.

There is some additional information in the adventure, including

details on placement of the traps and some important DCs for PCs finding them.



It also has this highlighted note on the intended effect of the teleportation traps:

Splitting the Party. Teleport traps are designed to split the party [...]

In a lot of D&D-like systems, there's the concept of a 'teleport trap', which is almost exactly what you're asking for. The first example that comes to my mind is the teleport traps in Nethack, which will send you randomly to a different location on the same floor, or possibly to a different floor for specific types, when you step on a specific square.

As for whether or not such a device exists in D&D 5e, I'm not sure. I know they explicitly existed in 3.5e because I've run premade campaigns for 3.5e that had them, but I've never encountered them in 5e before.

Barring the possibility of an actual teleport trap in the official rules, you have two options:

1. If you're playing rules-as-written.

You can create a similar effect by using a Glyph of Warding with Teleport (or another spell that can produce the required teleportation effect) as the stored spell, and a trigger of a creature handling the warded object. This has a couple of specific limitations:

• For most teleport type spells, it's dependent on how the DM interprets 'willing'. Personally, I see three ways this could be interpreted in this circumstance:
  
  
  1. The creature handling the object makes it implicitly willing, independent of whether or not the know about the glyph or want it to go off. In essence, they don't care what happens as a result of them handling the item. If I were to rule like this, it would be with some obvious indication that the item was magical, so that they would at least have the knowledge that they probably should be careful with it, which would actually make it the next case.
  
  
  2. The creature handling the object is willing only if they know about the spell. In other words, they know something will happen if they handle the object, possibly even what, and their decision to handle it anyway is functionally an explicit expression of willingness.
  
  
  3. They are only willing if they know about the spell and want the specific effect to happen. This is likely how most AL DM's will rule, as it's the closest to the established RAI for the Teleport spell.
  
  


• Barring the above, you're going to have to use an AoE teleport effect like a Teleportation Circle, which will of course teleport anything within range when the trigger goes off.


• Independent of either of the first two limitations, this is probably going to be a one-shot effect. Glyph of Warding triggers, and then is of course gone because the spell completed. You would need an effect equivalent to the old spell Permanency to make it a repeatable effect.

2. If you're playing with the opportunity of homebrew rules.

If you're the DM, just do it, there's no reason (provided your players know to expect non RAW items and such) to not do so. Just be careful you don't make it feel like you're railroading (as both a DM and a player, I would consider this a borderline case).

If you're a player, talk with the DM and see if you can come up with something together to get the desired effect. Most DM's love creative players.

In either case, consider the possibility of a high DC Wisdom or Charisma save to resist the Teleport effect. This can help players feel like they have some chance of not getting caught by it, and can also lead to some really fun gameplay if you're using an AoE teleport.