Lua Death damage ticking

[4Muki4]

Hello,
i can't script spells so i came here to ask help how can i add that when i use X spell on Y creature it takes damage 10 second like bleeding

local combat = createCombatObject()
setCombatParam(combat, COMBAT_PARAM_TYPE, COMBAT_DEATHDAMAGE)
setCombatParam(combat, COMBAT_PARAM_EFFECT, CONST_ME_MORTAREA)
setCombatParam(combat, COMBAT_PARAM_DISTANCEEFFECT, CONST_ANI_SUDDENDEATH)
setCombatFormula(combat, COMBAT_FORMULA_LEVELMAGIC, -1, -10, -1, -20, 5, 5, 1.4, 2.1)

function onCastSpell(cid, var)
    return doCombat(cid, combat, var)
end