What tool do you find the most interesting to date? (620054610)

The most interesting tool to date that I find on the abode illustrator is the pen tool. It may seem like a generic answer but in each class I learn something new to which the pen tool can do. It creates paths, can trace and can create accurate curves on a design. The pen tool in my mind is like the Tool that does it all. Currently no tool in adobe illustrator in my opinion can rival the pen tool and something which is a cut above the rest usually is the best.