In some ways, OOP was “grafted onto” Perl, particularly by means of the verb, bless, which sets a “blessed” flag and associates the object with a “class (equals package ...) name,” so that when you use the method-call (->) syntax, Perl knows what to do.   Most other programming languages “hide” the mechanics of “how OOP actually works” far more thoroughly than Perl does, and if you cut your teeth in one of those camps it will seem quite strange.   Yet, this is by design.