[Wakshaani]

For killing a Mega, the starting point is probably this:

Bring down Wal-Mart.

Wal-Mart's income right now is a bit higher than the megacorps in teh first corp guide, and it has teh international scope and scale or a Shadowrun mega. It's in dozens of countries, employs hundreds of thousands if not millions of people, and is diversified into a staggering number of fields, many of which you'd not expect. It tells suppliers how to make their products and what prices that they'll get, and if that drives a supplier out of business, too bad, they can always find another.

So, figure out a way for a team of five Shadowrunners to erase Wal-Mart, and you'll have a start on how to take down a mega. Mind you, the megas have extra-territorality, GOBS of guns, magic, and top-end Matrix support on top of this, so...

[Mirikon]

Let's put it this way, the whole Arcology debacle only wounded Renraku, didn't bring them down. The only one of the Big 10 to fall completely, IIRC, is Fuchi, and THAT took a great dragon's will and one of the three most powerful men INSIDE the megacorp playing the other two to take his piece of the pie and start a new mega (Novatech). Novatech got hit by the fallout of that same dragon's will, which caused Crash 2.0, but still survived by taking in the recent merger of Transys and Erika to become NeoNET, and stayed in the big 10. It takes something world shaking to bring down one of the Big 10, and even then they still might pull through.