HSOWA - Short for the phrase 'Hot Skitty on Wailord Action'. This phrase originated from a topic on the GameFAQS Pokemon Ruby/Sapphire boards when a user noticed that Skitty, a tiny kitten only six inches tall, could mate with Wailord, a HUGE whale, 47 feet tall. Then the user, Endgame, ended up saying 'HOT SKITTY ON WAILORD ACTION!'
And it started from there. It's been shortened to HSOWA ever since.
"Bow down to the HSOWA god Endgame!"