try this
25001,mega potion,mega potion,2,0,,10,,,,,0xFFFFFFFF,7,2,,,,,,{ sc_start SC_ITEMSCRIPT,180000,25003; sc_start SC_ITEMSCRIPT,180000,25004; },{},{}
25002,mega potion,mega potion,2,0,,10,,,,,0xFFFFFFFF,7,2,,,,,,{ bonus2 bResEff,Eff_Stun,10000; bonus2 bResEff,Eff_Freeze,10000; },{},{}
25003,stun dummy,stun dummy,6,20,,10,,,,,,,,16,,,,,{ bonus2 bResEff,Eff_Stun,10000; },{},{}
25004,freeze dummy,freeze dummy,6,20,,10,,,,,,,,16,,,,,{ bonus2 bResEff,Eff_Freeze,10000; },{},{}
enemy can dispel item # 25001
enemy can't dispel item # 25002
item # 25002
1. i dont know how long the effect will remove
2. if you die the effect still there
3. if you relog the effect will remove