This guide will let you know how to get the “Build Mode” Badge and Builder Piggy in Infected Developer’s Piggy. It will also tell you which map you will need to select to find these.
First, you will need to go to the Carnival map. 
Then head over to the top of the red and white lines hut. 
Once you’re there, you need to walk on the wire. 
Now do this Small Parkour and touch the Builder Piggy at the end to get the Badge. 
Make your way to the lobby and head to the Morphs Section in order to equip the Special Morphs. 