[MtG] Brutal Interrogation (and Exert)

[bury the year]

More "return to New Phyrexia" exploratory design. This is mainly to showcase the exert mechanic, which is only on Mirran cards and mirrors wither (which returns on Phyrexian-aligned cards). Exert embodies the desperation the Mirrans feel in their struggle to take back their plane. If you're short on resources, your creatures can make one final push for you, but they may become crippled - or even killed - in the process. A few things to note:

1. Exert is such worded that you can't put more counters on a creature than its toughness. With the example card, you can't drop five -1/-1 counters on a 1/1 token you control to cast it for {B}, as that would reduce its toughness to below 0 (in this case, -4). The maximum number of counters you could put on the token would be one, and thus the cost could be reduced to {4}{B} at lowest.
2. The normal cost for an exert spell will usually be at or slightly above its non-exert counterpart. This is because exert costs are much harder to pay in limited formats.
3. Exert will only appear on colored spells, and is most common in white, blue and black.

(Credit again to Rai for fancy templating.)