Protecto

Protecto (プロテクト) is a virus from Mega Man Battle Network 2. They never appear alone and they all need to be destroyed at the same time in one hit, otherwise, their HP restores back to their original amounts. Program Advances are highly recommended to defeat them.

There is a countdown timer on this virus starting at 10. When the timer reaches 0, the virus attacks with a field-wide explosion attack, dealing a total damage equal to one of the virus's HP. After the attack, the countdown resets back to 10 and starts over.

These viruses appear in specific locations of the WWW Areas, usually blocking a way towards a boss or an item. They also always appear in threes of one variant and never mixed with any other virus. Upon their deletion at the specific locations, they never reappear again.

According to a posting by one of the Undernet's regulars on one of the boards in Battle Network 2, the Protecto Viruses were sold to World Three (WWW) by someone who makes his own viruses, he may have also sold it to the Administrator of the Undernet as well.

Strategy
Due to having rather high HP and requiring the precise amount of damage to be defeated, Protecto viruses are considered rather difficult foes for several players. There are however a handful of ways to deal with them easily.

Protecto can be easily deleted with Time Bomb 3 (which at this point in the game is found regularly) or Zeus Hammer, although the latter is rather suicidal. Protecto 2 can be defeated with Time Bomb +, Life Sword or Ultra Bomb, Program Advances. Protecto 3 are the trickiest and normally would require very powerful Program Advances like Life Sword 3 (with some damage bonuses), however there is a much simpler way to defeat them, which also works with the other Protecto.

All the player has to do is use a Chip from the Octon virus family, right before the Protecto viruses attack. Doing so will cause the balloon to have a massive damage increase (usually enough or very close to the viruses HP). If lacking in damage the player can simply shoot the buster at the balloon to increase its damage (which should be an easy feat at this point with Level 5 Power and Speed) and have the balloon hit one of the Protecto, which will cause sufficient damage to nuke the enemy area and delete them in one fell swoop, completely bypassing the need for intricate chip combos. Since it has a capacity of 20 MB, setting them as regular chips should be fairly easy at this point of the game.

The only drawback of this tactic is the damage management as they have to allow the Protect to unleash their explosive attack in order for the balloon to gain its power, which can hurt quite a lot, although there are ways to prevent it. The player can use defensive chips like Barriers to survive the damage, or use a Style Change with defensive properties, or simply have enough HP to take the hit. If aiming for the use of Chips, the player can instead set Fast Gauge as their regular chip and navigate through their chips. They should have at least 2 turns after the initial turn, which is ample time to get them and use them.