Shouldn't you try to invite him for a beer and talk about it? Also, be careful when stamping the "toxic" label. I'm not saying you're wrong in your judgement,

Shouldn't you try to invite him for a beer and talk about it? Also, be careful when stamping the "toxic" label. I'm not saying you're wrong in your judgement, but maybe you just don't know what's happening with his personal life. I have a fellow colleague which I always considered at least "cranky" since I joined my current company (half a year ago). Last week we traveled to work abroad and had some free time to talk over beers - he confided me that his mother was and still is very sick. Tough stuff, which reminded me clearly how frivolous we all can be when making judgements.