Ikoria is here and with it its new Mutate mechanic. It's definitely a rather complex mechanic for a Standard legal set, but it's also quite interesting as it only works for non-Human creatures for flavor reasons. Inspired by this, your new challenge is:
Design a mechanic interacting / caring about / requiring / similar one or more creatures that excludes one (or up to three at maximum) tribe(s).(The point is to indeed come up with a mechanic, even if it's just a pseudo one, rather than desiging a one-off card like Call to the Grave, f.e.)
Have fun, everyone!
Please remember: You're not allowed to vote for yourselves. For further information please look at the CotW Rules.