What was TNG's very best 'Mindscrew Episode'?

[WhitneyKay]

Night Terrors from season four.

Agree

 

[Mojochi]

No mention of Timescape?

I'm still not sure what happened. Some aliens took the form of Romulans, then beamed over to the Enterprise while the Romulans gave chase onto the Enterprise? Was that it?

Not really

The Romulans' warp engine failed when the aliens tried to use it as an incubation chamber for their young, mistaking it for a naturally occurring quantum singularity (a black hole)

The Enterprise responded to their distress signal, assumed they needed power for their engine & initiated a power transfer beam, which ruptured space/time, caused catastrophic failure on the Romulan ship, endangered the alien young, & eventually overloaded the Enterprise's warp field causing a breach.

Romulans began evacuating to the Enterprise. One of the aliens in Romulan form went along to try to stop the power transfer, while the other one gained access to the Romulan ship's weapons & opened fire on the Enterprise, for the same reason

This is the point the runabout crew found them, incapsulated in a bubble of decelerated time, just shortly after Picard had to trim his fingernails