I know PHP so I made something like Brainwallet brute force... I made it record every address that has been used then it will monitoring all founded address because maybe they will be used again in the future.
So I founded a lot of address where 0.00005460 BTCs are received and 0.00005460 BTCs are sent. That's it. Why this amount and why so many addresses

i think it was a researcer doing tests in that pariod. The completly list of the words used was about 17k words.
no, it was a spam attack against bitcoin network which they called "stress test"! basically at some point they tried to get others involved and try to flood the network with double spends. so they sent a ton of transactions to addresses with known private keys (which a lot of automated scripts are watching to steal their coins) and also a lot of coins to other keys which they released later:
https://bitcointalk.org/index.php?action=profile;u=553487;sa=showPosts to cause a lot of traffic between nodes sending double spends. and to simply make people do the spam attack for them!