Gogo, Master of Mimicry

Gogo's ability targets an activated or triggered ability that is on the stack and creates one or more additional instances of that ability on the stack. It doesn't cause any object to gain any abilities.

The copy will have the same targets as the ability it's copying unless you choose new ones. You may change any number of the targets, including all of them or none of them. If, for one of the targets, you can't choose a new legal target, then it remains unchanged (even if the current target is illegal).

Gogo's ability can copy any activated or triggered ability on the stack, not just one with targets.

The copy is created on the stack, so it's not "activated." Creating the copy won't cause abilities that trigger when a player activates an ability to trigger. Abilities that say that a triggered ability triggers additional times won't apply to copying a triggered ability.

Any choices made when the ability resolves won't have been made yet when it's copied. Any such choices will be made separately when the copy resolves. Most notably, if a triggered ability asks its controller to pay a cost, you pay that cost for the copy if you wish to have it paid.

The copy will resolve before the original ability does.