One great example-
The fruit in the Forgotten Temple of Tharizdun.
There was a room with five trees, each with fruit of a lustrous black color. The five trees were coded to classes (one was F, one Cl, one TH, one MU, and the last one was everyone). If a character from the correct class picks a fruit, then they have to make a system shock check.
If they fail, they are turned to black ash, forever gone. If they succeed, they gain a point in their main ability.
If they do it a second time, they have to make a system shock. If fail, death. If succeed, the LOSE two points in their main ability.
If they choose the wrong tree, they take 3-30 damage, and must make a system shock as above.
Another wrong tree? 3-30 damage and reverse system shock.
Third wrong attempt? Just death.
The "bonus" tree will give anyone either a point in constitution or charisma. No check required! But if they try again, or if this is their second tree, they need to do a reverse system shock roll (or die forever) AND lose a point every ability.