Floshell

IronShield are a family of viruses from Mega Man Battle Network. They resemble a mechanical lizard sans the tail (wherein they have two antenas portruding upwards). These viruses also have a shield throughout the battle, which makes them invulnerable to attacks. However, when attacking, these viruses raise their shields up in order to eject a cannonball. They can be damaged only during their attack, when their shields are raised.

IronShield1
IronShield1 are machine cannons on four legs with two antennas. They are pink in color with a grey shield.

IronShield2
IronShield2 are machine cannons on four legs with two antennas. They are tan in color with a red shield.

IronShield3
IronShield3 are machine cannons on four legs with two antennas. They are whittish in color with a yellow shield.

Trivia
Interestingly, whether by coincidence or by choice of the programmers/game planners, the possible chip codes for the chips dropped by IronShield1 spell out "ABORT".