The "with" keyword in Delphi.
It allows evil code like this:
SomeObject.SomeProperty := 'Value1';
SomeOtherObject.SomeProperty := 'Value2';
with SomeObject, SomeOtherObject do
begin
SomeProperty := 'Who Knows which one is being set!';
// 50+ lines of code using the Objects without needing the actual object.
end