Masking out Text in Premiere Pro 2019
I would duplicate a copy of your background (doggy) layer.  Put it on top of your text layer, then animate the mask on your foreground layer. So in total you have three layers:

V3 - foreground dog (masked)

V2 - text credits

V1 - background dog (and everything else)


(I reckon masking like this is easier in after effects but can be done in Premiere)