Pyrophobia

Coward is a creature type. You won’t see this creature type printed on creatures (perhaps because they’re too good at hiding), but keep in mind that creatures with the changeling ability are Cowards.

If the target creature is an illegal target by the time Pyrophobia tries to resolve, the spell doesn’t resolve. Cowards can block if they’re otherwise allowed to.

Because it doesn’t modify the characteristics of creatures, Pyrophobia can affect Cowards that enter the battlefield or creatures that become Cowards after the spell resolves.