On Item Pickup

function onPickup  takes Item itm returns nothing
    set itm.userInt = 0 
endfunction

On Spell Cast

function onSpellCast takes Item itm returns nothing
    set itm.userInt = itm.userInt +1
    if itm.userInt >= 5 then
        call itm.getCarrier().addSpellCrit()
        set itm.userInt = 0
    endif
endfunction