CL4P-TP (also known as a "Claptrap Unit") is an NPC in Borderlands: The Pre-Sequel
You meet a CL4P-TP unit first in the beginning of the game, at the Helios Station
It urges you to follow it so that you can get to Jack
On the way, you need to defend it from some Lost Legion Marines that attack it.
"Open for me, oh door!"