Bast Statue

The buff reaches across a huge rectangle, roughly what a Heart Lantern covers, so one placed at the center of a boss arena blankets the whole fight. Two of them do nothing extra, which trips up people who line them along a platform. Wire it if you want it off for a challenge run or for a farm where you would rather not buff anything.

Flat defense is worth the most when your total is small, so grabbing one before the first bosses is a bigger swing than it looks on paper. Sandstone Chests deep in the Underground Desert are the usual source, and it also turns up in the desert cabins down there and in Oasis Crates. One statue at every arena and every farm is a normal way to end up using them.

Bastet was the Egyptian cat goddess, associated with protection among many other things. The buff name is a play on the old line about the best defense being a good offense.