The article explores how spiteful bidders in auctions can affect their bidding strategies. Spiteful bidders care about both their own profit and their competitors' losses. In 1st-price auctions, spiteful bidders tend to be truthful. Surprisingly, the number of bidders doesn't affect the equilibrium strategy in 2nd-price auctions. Expected revenue is higher in 2nd-price auctions when bidders are even slightly spiteful and care about their own profit. Revenue equivalence only holds when all bidders are either self-interested or completely malicious. Revealing bidders' valuations reduces revenue in 2nd-price auctions but increases it in 1st-price auctions.