Tensei Youjo.: Shinjuu to Ouji to, Saikyou no Oji-san Youhei-dan no Naka de Ikiru - Ch. 34

[MangaDex]

 

[DHJones]

Wait... is it her Earth dad?

 

[Flyingpantsu]

Given how colorful the usual casting is, the chance of Lize being the young girl in question is actually not as high as it would normally be.

 

[JACGohu]

I'm a little foggy because of the release pacing. What lightning tool was that again?

 

[MilConDoin]

I'm a little foggy because of the release pacing. What lightning tool was that again?

You can see it in action in ch 21, page 9 for example.
It was made from the bargain bin at Pinky's. I think it was about creating electricity with the help of lava (the mole people had access to a lava lake). And then shooting lightning lances at the enemies.
I forgot if Lize herself was included in converting the attack power into other uses, or of the mole people managed to make that leap themselves.