Characters Inducing Stupidity

Summary
Character-Inducing Stupidity (known as CIS; Character-Induced Stupidity) is a term used to define an event or happening that contradicts the character-induced mental and/or physical abilities and/or characteristics of one or more characters.

Unlike Stupidity-Inducing Plot, this happens when the character himself is limited by a cause. It can also happen when the character is powerful enough/fast/durable but not smart enough.