How would you do a pop up lower third shape ?

I have a typewriter title running with some telemetry - let me know if you need, I can send you btw. 
But the text on screen looks rubbish on its own over the picture.
How might you slide in a shape or something for it to go over? 

Specifically what title template are you talking about?

You have two options:
1, Right-click the title template and open it in Motion, add that element and Save As.
2, Go to Generators > Solids > Custom, add that just below the title, Crop it down to be only behind the text, the set the color and opacity as desired.

As Ben suggested Custom shape cropped to the size you need is a good option.

If you want to have the blocks behind your text automatically sized to the size and length of your text that is a quite a bit more complicated.

For my last project I created 2 title templates in Motion for that purpose.
You can download them here: Link . Place the folder in /Users/Movies/Motion Templates/Titles
Rather than using the typewriter letter by letter I opted for a word-by-word build in because it looks a bit more elegant. The actual auto resize of the blacks behind the text are quite a bit of work in Motion. Open the templates in Motion if you would like to study how I did them.
When you apply the templates in FCP you get quite a few options for adjustments in the title template inspector plus you can of course change the font and it's size via the normal controls.

Maybe this is what you need or gives you an idea how to 'bake' you own.

I found this animated one now in the meantime - Simple Lower thirds. Plug in on Envato elements. 

I did wonder about custom solid ... shame you can't have a rectangle or something and kf it in. But this looks ok 

I just deleted text and put my own over it ... time consuming but then I suppose that part of edit always is. 

Thank you gentlemen.

You need to build it in Motion and publish it as a Title template, will save you a lot of time if this is reused a lot.

oh heavents... #zero "build it in motion" skills

Learn Motion, easier to use than you'd think. Take the macProVideo or RippleTraining course.

Thanks boyz - and yeh I hear you on the course.... that and a PS for thumbnails... maybe I will. Give me something to do when I am N O T D O I N G A N Y W O R  K