How did Babidi know the appearance of Goten/Trunks?

[SSJ2]

When he was broadcasting to the earth, he produced an image of Base Goten and Trunks when he only saw their SSJ forms.

 

[Papasmurf]

Babidi was still alive/conscious when Vegeta knocked them out, so I guess he saw them then.

That or

 

[SSJ2]

Wasn't he pretty much buried in the ground? lol

 

[Let's Go Fearless!]

He can read Boo, Vegeta and Piccolo's mind.

 

[Papasmurf]

Wasn't he pretty much buried in the ground? lol

He could still erect a barrier, so I guess he was kept awake by the feeling of his severed spine.

 

[withheldforprivacy]

How did Anime Gohan know the appearance of Perfect Cell when he dreamt of him in the spirit room?

 

[Papasmurf]

Cell secretly went back in time again after turning perfect and banged Chichi so hard her children would instinctively know his face

 

[Let's Go Fearless!]

How did Anime Gohan know the appearance of Perfect Cell when he dreamt of him in the spirit room?

Probably he watched him on TV.

 

[theallpowerfulpuipui]

He can read Boo, Vegeta and Piccolo's mind.

Great answer, I was going to say that Toei was trying to save money.

 

[Captain Cadaver]

If Babidi were capable of reacting somewhat to Boo's stray Ki blasts enough to dodge them, I don't see why he wouldn't have good enough eyesight to spot SSJ Goten/Trunks.