This can now be on warlocks

But only if you have bought Tasha's Cauldron of Everything.

If you are wondering why The Simbul never let anyone know her name in her century on the throne of Aglarond, it was so the Red Wizards of Thay could never pull this level of magical assassination deathtrap nonsense on her.

The best use of Psionic Sorcery from the Abberant Mind Subclass.

Quote from Dartagnan_Galochio >>

The best use of Psionic Sorcery from the Abberant Mind Subclass.

Psionic sorcery only works for the subclass' bonus spells. Not the expanded spell list for the whole class or the PHB spells.

Can attacks, spells, and abilities pass through the portal?

Quote from VigilantUnicorn >>

Can attacks, spells, and abilities pass through the portal?

Through its front, yes. Portals in D&D 5e effectively put two places next to each other, for the portal's duration.

Quote from MiniDeathStar >>

Quote from ironic_dragonborne >>

Another good use for this one is a railgun. Make two portals above each other vertically.

~

 Not with this spell though, it specifically says the exit portal must be on a different plane.

That's why they specified using two Gate spells, each with their exit above the other's entrance. I believe you'd then need a third casting though, to intercept the falling object with a Gate exiting toward your target.

If I recall correctly, the maximum damage from a falling object is 20d6... so if that's a character's best use of three 9th Lvl spell slots, they should just give that Black Crystal Tablet back.

Quote from ProphetZarquon >>

Quote from MiniDeathStar >>

Quote from ironic_dragonborne >>

Another good use for this one is a railgun. Make two portals above each other vertically.

~

 Not with this spell though, it specifically says the exit portal must be on a different plane.

That's why they specified using two Gate spells, each with their exit above the other's entrance. I believe you'd then need a third casting though, to intercept the falling object with a Gate exiting toward your target.

If I recall correctly, the maximum damage from a falling object is 20d6... so if that's a character's best use of three 9th Lvl spell slots, they should just give that Black Crystal Tablet back.

 Seems like a lot of effort for something a Wizard can achieve on its own with a single casting of Arcane Gate XD 

Quote from Furujiru >>

Seems like a lot of effort for something a Wizard can achieve on its own with a single casting of Arcane Gate XD 

Sorcerers can as well, so I'm not really sure what the idea is with using Gate for such a weird purpose.

If you want to hurt someone with Gate and don't know their name, well just pop into your local library, learn the name of a chromatic dragon, hide behind a rock with an escape route behind it, summon the dragon on top of that one guy who called you a mean name once, then run in the opposite direction.

For those who (like me) are terrible at remembering names, just pop to a few elemental planes, take a note of some particularly nasty liquid or gaseous environmental features (or irate denizens) and summon your gates to connect them; dump lava on your enemy's head, fill their house with vampire mind flayers etc. etc. 😈

Quote from Mandabar >>

Quote from MayaaaLuna >>

Can this spell be used to extinguish large fires?

 Perhaps, if you open a gate to the elemental plane of water... no telling what else comes thru withe the water, and how pleased it will be about being sucked thru though.

You may also need to KNOW an 'precise location' on the plane to open the gate there.

 There is no pressure in the elemental plane of water, due to it's lack of gravity, so nothing would be pushing the water out of the portal.

i'd rule yes

is that cannon in 5e?

Hello 

Hi

Hello

Quote from Seanpeery >>

Quote from Mandabar >>

Quote from MayaaaLuna >>

Can this spell be used to extinguish large fires?

 Perhaps, if you open a gate to the elemental plane of water... no telling what else comes thru withe the water, and how pleased it will be about being sucked thru though.

You may also need to KNOW an 'precise location' on the plane to open the gate there.

 There is no pressure in the elemental plane of water, due to it's lack of gravity, so nothing would be pushing the water out of the portal.

 There is gravity on the Material plane pulling it, however.

Yes

i noticed it said GM

Can I use this spell to summon Tiamat?

Yep... assuming Tiamat is currently on a different plane than you are.