come up and bite

verb2

1. •
   (informal) To be extremely obvious to (someone), to be impossible for (someone) to miss and ignore.

   • These new recruits are terrible soldiers. They wouldn't know what to do with an enemy if one came up and bit them.
2. •
   (informal) To clearly expose itself to (someone).

   • You really think you can convince the committee? Come on! You wouldn't know charisma if it came up and bit you.