Mettaurs
Mettaurs, they are in every Megaman game, they are weak and pathetic, that's why they are dangerous, because ignorant people underestimate their power, in Megaman Battle Network, they are fairly weak compeared to a number of other Virus, butthey are a bloody handful in Megaman Battle Network 4, particuly the part when you defeate Bass and you need the 5 Evil Chips to follow him to Black Earth.
at the begining of the game, the Mettaur Virus can be a bit of a problem to the begginer, but can easily be S-Ranked and rack up a fair number of Guard1 Chips, the speed of their shockwave is very slow, dude even the MettaurEX Virus is a bit slow with the attack, and you can easily counter them almost every time, but if you think Mettaur Viruses stay that easily, your wrong, MettaurEX Viruses hold the ability to hid in their little hat sheild when it's not their turn to attack and every other Mettaur Virus after MettaurEX has this tactic, the hat will stop any attack but the good old GunSol Chips and the even better GunSolEX, and the Geddon3 Chip will also make them squirm.
the Mettaurs have a number of dissadvantiges with them, the move up and down only, the shockwave the make can't go across a hole and if there is a virus in their line of movement, they wont push it out of the way.
the real bastards are the Mettaur3EX, the black ones you fight in the Undernet in Continue3+, and you also face them in your trial battles when you are getting the Evil Chips to get to Black Earth, their attacks are very fast so they hid quicker, and they move very quickly, unless you can take out one collom of pannals or use Geddon, you really don't get a chance to hit them.
so remember when fighting any of the Mettaur Viruses in any Megaman Battle Network game, don't think for a second that they are a peice of cake, think that and your dead