In US gov treasury auction, can the highest bidder force high prices for all others In US treasury auction (for bonds and notes), my understanding is that the highest bidder's price (and rate) is applied for all the buyers. 

Assume a buyer 'A' who plans to buy a smaller number of bond shares. Let two other players 'B' and 'C' invest heavily compared to 'A. Let 'B' and 'C' be competitors of 'A'.

Is it possible for 'A' to invest low but bid high thus play spoilsport for 'B' and 'C'?
No. The auction uses the highest yield, which means the lowest price (for the same coupon). That is, for bonds, price up -> yield down (and vice versa). (The only tricky bit is that the coupon is not known until the auction concludes.)

For a discussion of U.S. Treasury bond structure: link to TreasuryDirect.

Not all bonds are issued via an auction process (one alternative is “tapping” issues). Sweden is an example of using a multi-price auction - link to Swedish auction description.