Fun item, just rife with possibilities from the mundane to the absurd. It could be a door stop or a anti theft device inside a safe/chest. Hide one on a ship and hold it ransom. Attach it to a weapon such as a heavy duty lance or shield to take the force of a charge from a large critter, even if the lance/shield breaks the rod is still going to hurt as the creature runs through it. Use two to climb to the sky, although slowly. Set a trap for a heavy foe, just load up a bunch of rocks or other items held in place by the rod and some sort of mechanism to apply the weight of the creature also to the rod and after the 8k in force is achieved it all comes crashing down. Tie a rope to it and a person to the other end  of the rope and who knows what fun could be had. Eaten by a purple worm, activate the rod and hold on, as the worm moves, the rod stays in place, possibly creating a way out. Add a elastic rope or something else strong and stretchy and in a pinch it could save one from a fall.

Only sad part is mage hand can't be used to activate the rod.

I agree.^^

Although, I have to ask, who says that Mage Hand can't be used to activate the Rod? I mean I can understand that certain DMs may indeed want to make that a thing in order to avoid too much cheese being done with it, but I see nothing in the actual description or rules.

Immovable rod + sovereign glue= best prank to pull in a sleeping enemy. Glue takes one minute to set. Have the roughest sneak up and place it between their shoulder blades with the glue on it. One minute later: Push botton, wake up the sleeping baddy and watch as hilarity ensues.

These would be useful as "air anchors" on an Eberron airship, as long as you can attach it to the "keel" and it activates over several seconds instead of instantly.  Useful if you're trying to get on your ship elemental's good side instead of treating them like an engine and nothing more.  

"Captain, Auira would most likely appreciate an 8 hour break before we start crossing the desert, sir.  Plus, I can take Stormfeather and go hunting for provisions while the crew refills our reserve water tank."  The first mate gestured to his gryphon steed who was noticeably growing restless in his corner nest he had built in an opening to the lower decks.  

"Agreed, Mr. Irons.  I'll let her know to take us to around 300 feet about the water and to hold us as steady as she can.  You can activate our immovable rod."  The skycaptain peered through hs eyeglass at the coast and beyond to the endless sea of dunes.  

"We won't be landing, Captain Lyrandar?  We could set down in the water just fine if you're worried about..." The brass scales on his eyebrows gleaming as they rose inquisitively.

"It's not the seas or the sand that worries me, Mr. Irons.  This will be a 3000 mile flight across burning sand.  I want the whole crew to get a nice long rest while you and I take watch, and I'd like my chances better if we were in the air."  

The ship steadied in the coastal winds as Vos went to the ship's core.  He grasped the two horse-embossed ends in his hands and waited for his captain's whistle.  As soon as the leveling tool was in proper position, he slowly but firmly began to twist the two ends to face the same direction.  The ship's floors creaked slightly as the ship's weight was gradually set upon its internal metal frame.  The ship hung suspended in the air as if it were the moon in the night sky.

Mage hand cannot be used to activate magic items

Ah! Well I suppose that would make fair sense in any event, wouldn't it?

Thank you!

But Tiny Servants can...

And Imp familiars...

hey if u stick one off these rods into a open wound of a creature that regen would it heal around it or push the item out(serious question no jokes please i've thought of ten just by writing this)

Kind of weeby, but can you use this like Pain's rods from Naruto? that would have cool combat potential

Also how long is this rod?

@Puregrey Use them like Pain's rods in what way?  I don't recall them stopping people from moving, they just drained chakra.  Pain had to pin Naruto down with a whole bunch of rods through his hands, legs, arms and body to stop him moving.  That said, you could likely put it down on someone and activate it in the style of Thor's hammer to prevent them moving.  Though unless they are restrained, they can just push the button themselves.

Rods are.. well, rods.  It's 2-3 feet in length.  They are shorter than staves.

@ReaverBroodCleaver There is not, and never will be, any actual ruling regarding something like that.  That would be completely up to the DM.

How many daggers could you glue to this?

8,000 pounds of daggers

Which means 6526 daggers, with just under 0.625 pound to spare

Damage?

l hope to get this for if i ever find myself in the air (falling from cliff,eaten by dragon ect) so i can use this and slowly make my down to the ground by pressing it on/off quickly to slowly fall. (who needs fetherfall when you have one of these)

@DnDNewper

Interesting idea but it takes a full action to push the button so unless you can figure out a way to do it as a bonus  action youre going to fall 500 ft by the time you can push the button the 2nd time. Might be able to stop yourself before you hit the ground but I'd rule that as requiring a successful strength check to hold on when the rod stops suddenly.

 a action is six seconds right? how far can you possably fall in 6 seconds? and even if you still take some damage from the fall,it will still be less then the hundreds of damage from one non stop fall. also lf you are a mage,you could cast haste on yourself to help with this. (and before you ask,you should be able to count as a willing creature,and you can use a object,which this is.)

@bethnal and @dndnewper

You will fall 120 ft in the 6 seconds me and my buddies had to know. I'm hoping to get my hands on 2 rods

I like how everyone completely ignores the weight limit. No people, you can't hold a giant or a ship in place with the rod, they would easily deactivate it.

I know this is super old but doesn't Immovable hand say that it can't use magic items?