BOMBERMAN ActZero

You get these by both killing people and winning Battle Royal matches in a row. Every person you kill in a Battle Royal goes towards this total (which you can see next to your name as you play the match) but if you get killed even once while in a Battle Royal.. the number will reset. This makes them very difficult to obtain legitimately.

Getting anything above 30 is nearly impossible without boosting.

To get this, you have to kill up to 100 enemies in a row without dieing in Battle Royal, even if you kill yourself while the game ends in a draw. However, it doesn't count towards your count if your enemy dies to one of his own bombs or due to falling blocks.
But you don't have to do this in one sitting, as it saves your count as long as you don't die.

If you manage to kill 7 enemies with your bombs, you get 7 points in one game. But you have to be lucky to find even one gamer to play with.

My suggestion would be to boost it with as much friends as possible. If they already have some points, let the player with the most start to boost, obviously. Start a FPB Battle Royale (just in case you accidently stumble upon your own bombs). Tell your 7 buddys to stay still while the one who's boosting kills one by one. With that it will only be 15 games until one reaches 100 consecutive Kills. Rinse and Repeat.

I boosted it with only one friend, and it took ~3-6 hours for one player.

By doing this you also get a lot of Battle Score.