This card is not for everybody. If you're building a fun chaos deck to be used to induce headaches in multi-player games, though, you can't pick a better one. Note that the trumpet's power affects everyone on play including yourself - it is entirely possible for the trumpet to discard itself. Another disadvantage is that you have to discard a card out of your draw pile to use the trumpet. For example, you could draw and discard your The Caravan (131/4th) and wind up discarding all of your own magic items in play to boot.

The trumpet must be used each phase three. It is not an optional use - you must blow it each turn. There are several strategies you can use to minimize the damage to yourself. First, and most obvious, do not load up your deck with the types of cards that the trumpet discards. Second, when you first put the trumpet into play, use it at the start of phase three, before you lay down any more cards into your pool that the trumpet might affect. Last, use it in conjunction with the rule card A Sure Thing (74/NS). You don't have to discard a card out of your draw pile to use it, you would instead choose the desired result. The result still applies to all players, including yourself. This allows you to inflict maximum damage on your opponent if you are willing to suffer the same affect.

You won't win many games with the Trumpet of Doom, but you will get many games worth remembering.