What happens if a Larkin eats a shard? Or Nightblood?

[Mistspren she/her]

Could a Larkin inhale an entire shard? Would they become planet sized? I’m really curious to see if this is possible. Would the larkin just pop?

Also, if Nightblood and a Larkin tried to eat each other simultaneously, what would happen?

[Weltall]

Brandon has said that Larkins and Nightblood are similar in the way they leech Investiture. He's also described Nightblood as being an order of magnitude more powerful than an ordinary (living) Shardblade. Now consider the following WoB:

Quote

Questioner

If you were a Leecher, could you destroy a Shardblade?

Brandon Sanderson

I'm going to RAFO that for now, let's just say that it would be incredibly difficult if it were possible, and I'm not going to even say if it is. But that kind of power... 

Questioner

Let's just say they were burning duralumin as well.

Brandon Sanderson

Let's just say that the Investiture in a Shardblade is much greater than your average Allomancer, but... This type of thing is not unheard of in the Cosmere. The larkin, the Leechers, and Nightblood all have a similar sort of thing going on. Destroying a Shardblade would be really hard. And Investiture resists other forms of Investiture, so.

source

Ergo, it may not be possible to drain the Investiture from Nightblood at all and if it were possible it would be really really hard. And Nightblood would be resisting so it's likely the end result would be the Larkin fleeing in terror, deciding that Nightblood is a god and beginning a cult dedicated to it or getting imploded by Nightblood trying to leech it.

Also, Brandon has said that Nightblood isn't powerful enough to kill a Shard, though he's been deliberately vague on just how much damage it could do to one. There's no way a Larkin could do better than that and it would probably get splatted like a bug if it tried. Assuming you could even get a Larkin into a position where it could try to leech a Shard, given that they're mostly in the Spiritual Realm.

[Mestiv he/him]

55 minutes ago, Mistspren said:

Also, if Nightblood and a Larkin tried to eat each other simultaneously, what would happen?

I'm afraid a Larkin would get zapped like a mosquito hitting electric mosquito trap. Larkins probably have less suction power than Nightblood.