Arsenal Thresher

As this creature enters, you may reveal any number of other artifact cards from your hand. This creature enters with a +1/+1 counter on it for each card revealed this way.

Planechase

As Arsenal Thresher enters the battlefield, you may reveal any number of other artifact cards from your hand. Arsenal Thresher enters the battlefield with a +1/+1 counter on it for each card revealed this way.

Alara Reborn

As Arsenal Thresher comes into play, you may reveal any number of other artifact cards from your hand. Arsenal Thresher comes into play with a +1/+1 counter on it for each card revealed this way.

If Arsenal Thresher and another artifact are entering from your hand at the same time, you may reveal that other artifact for Arsenal Thresher. If that artifact is a second Arsenal Thresher, you may reveal each Arsenal Thresher for the other.

If multiple Arsenal Threshers are entering at the same time (for example, if Warp World is resolving), you may reveal the same artifact cards from your hand for each of them.