Residual Effects

You have endured countless magical experiments. Your body gives off a faint shimmer in certain light and at certain angles, a testament to your longevity. Side effects include:

A Faint Glow. You radiate a faint magical aura due to your exposure to potent magic. As a result, you can be detected by a Detect Magic spell or similar effect.
Arcane Synesthesia. You can taste certain spells, smell certain magical effects, and associate the flavor of potions with colors, numbers, or memories.
Tingling Sensations. Years of exposure to potent magic have sensitized you to its aftereffects - subtle fluctuations and distortions of reality that usually go unnoticed. As part of an Intelligence (Investigation) check, you can determine if a 4th level or higher spell has been cast within the past week. If it has, you can spend an hour concentrating to identify that spell. Make an Intelligence (Arcana) check (DC equals 15 + the spell's level). On a success, you identify the spell. On a failure, you only learn the spell's school. If multiple powerful spells have been cast within that time, you can only identify the most recent.
Mild Paranoia. Pick a school of magic. You distrust it.