Agitator Ant

Attacking with a goaded creature doesn't cause it to stop being goaded. If there is an additional combat phase that turn, or if another player gains control of it before it stops being goaded, it must attack again if able.

If a creature you control has been goaded by multiple opponents, it must attack one of your opponents that hasn't goaded it, as that fulfills the maximum number of goad requirements. If a creature you control has been goaded by each of your opponents, the creature must attack an opponent (rather than a planeswalker or battle), but you choose which opponent it attacks.

As Agitator Ant's ability resolves, first you choose which creature you control, if any, to put two +1/+1 counters on, then each other player in turn order does the same, knowing the choices made before them. Then each chosen creature receives its +1/+1 counters and becomes goaded.

If a creature can't have +1/+1 counters put on it, its controller can't choose it just to have it become goaded. If it can have counters put on it but replacement effects cause it not to receive +1/+1 counters, it doesn't become goaded.