Most of the time you'll be able to put that counter on another creature, maybe even a green or black creature that takes advantage of having -1/-1 counters placed on it, like Channeler Initiate
Cool but Rude The tutor is arguably the least of Cool but Rudes abilities
The results of that damage are the player loses 2 life and gets a poison counter.
Blanked foils printed over with art made by creators like TheProxyGuy or SheepWave on Twitter, custom printed cards with different art and backs, cards printed on paper in sleeves, painted over MDFC checklist cards, all the way down to Sharpied basics are all fine
However, the risk of losing life for each exiled card can be detrimental, especially in formats where life total matters
You're in position, ready to attack, and is on the perfect line of sight