Mogg Flunkies can be declared as an attacker only if another creature is declared as an attacker at the same time. Similarly, Mogg Flunkies can be declared as a blocker only if another creature is declared as a blocker at the same time.

Two or more Mogg Flunkies can attack or block together.

Although Mogg Flunkies can’t attack alone, the other attacking creature(s) doesn’t have to attack the same player or planeswalker. For example, Mogg Flunkies could attack an opponent and another creature could attack a planeswalker that opponent controls.

In a Two-Headed Giant game (or in another format using the shared team turns option), Mogg Flunkies can attack or block with a creature controlled by your teammate, even if no other creatures you control are attacking or blocking.