This wasn't an average night thankfully.
In their field, Pippin can be indeed a pipsqeak, or what you'd call a "total dick!" Merlin will be minding his own business, grazing, napping, peeing, doesn't matter. I'll see Pippin shake his head and "kablam", he's charging and harassing Merlin. Pippin is much faster and can get away before Merlin realizes what's hit him. Pippin takes off like any little brother who knows he's pissed big brother off big time.
When I stall them for the night, I've found letting Pippin in first is the best way to go. They each head to their bowl quietly & eat. Merlin first I can just about guarantee chaos! He'll kick out with both barrels, backing into Pippin on some nights as he comes in. I'm just guessing but, perhaps he's 1. Letting Pippin know he's not taking any shit or 2. REVENGE for the days/weeks events? This night was no holds barred.
Pippin may have been worse than usual in the field that day! Last nights full moon they came in nearly holding hands oddly enough.