The Cannon Cannon is a weak card, but it has an effect that can help bolster the owner's hand.
This card was made by Kaynato.
Cannon Cannon can be played face down.
When flipped face up a random card with cannon in it's name is added to the owner's hand for free. Additionally, when this card is on the field the owner may pay 250 Points and forfiet their attack for the turn to add a random card with a cannon in it's name to their hand. In theory, it is possible to achieve more Cannon Cannons either way.
It is not stated if the card needs to be face up to use it's secondary effect. Presumably Cannon Cannon does have to be face up.