Pigman Δ
Retinazer
No, don't. This is called a CHEESE and it is where you fight the boss unfairly and with no skill used.just search how to defeat plantera with teleporters, and done
EDIT: (btw yes, plantera is very hard first time, the main thing you need is a huge area and lots of mobility, then the spiky balls will stay at the bottom of the arena while you fly above)