This is a fairly unique trauma signature weakness. Looking at the two elements, the effect and the discard condition, we get:
The effect: You take direct damage and trauma, mental or physical, your pick. Normally, this would be disastrous, but Calvin likes trauma, right up until he doesn't. There is no real mitigation, except not getting trauma outside of this card or, maybe, limiting drawing as much as possible. If the direct damage defeats you, you are getting 2 trauma, and once Calvin hits 6 trauma of either sort, you are out of the campaign. If you can get down Five of Pentacles, Until the End of Time, or any of the other soak assets, you can keep going with even very high trauma, but, if you draw this every scenario, you will be on very tight margins.
The discard condition: One and done. You take your trauma, and you take your chances.
All in all, this is an average signature weakness. It's managable but can end a campaign.