Etherwake's magic packet is strange

So, here is what i already know about WoL's magic packet without password.

FF FF FF FF FF FF [MAC_ADDRESS] [MAC_ADDRESS] [MAC_ADDRESS] ...

My etherwake works fine. but just in case, i captured a packet using wireshark.
PC is already ON, and i ran a wireshark at the same PC

And here is the packet.

# Source MAC = AA:AA:AA:AA:AA:AA
# Destination MAC = BB:BB:BB:BB:BB:BB

BB BB BB BB BB BB AA AA AA AA AA AA 08 42 FF FF FF FF FF FF BB BB BB BB BB BB ...

i've searched at google with "WoL magic packet wireshark", but the packets shows like the one at the top, not the second one.

i think i can understand why there are Source MAC, and Destination MAC, BUT i have no idea what is that 08 42 is.

any ideas?