One card should not be able to win fight this makes the game pointless.If I don't use all my pills to stop a possible attack they just fury and win it really takes away from the strategy of the game.
Kolos is actually one of the more 'bluffed' cards in the game. People expect you to go all out so you can 1-pill Kolos and end up at a huge pillz gap. Oh, and if your opp's Kolos plays first and you have a damage reducer, just throw them out. Your opponent may expect it but it saves you from a 1HKO and the move tastes sweeter if your opp goes all-out and wastes their pills on a thwarted 1HKO.
Having multiple DRs and an SOA handy always helps against most OHKOs - refer to the stickied thread
DRs and SOA used to be more scarce 1-2 years ago, but nowadays they're pretty affordable.