Activate this card by discarding 1 monster, then target 1 monster in your Graveyard whose Level is lower than the discarded monster's original Level; Special Summon it and equip it with this card. The equipped monster has its effects negated. You can only activate 1 "Overdone Burial" per turn.
Special Summons monster that is lower level than the discarded monster’s original level, from the Graveyard to the Field.
The Special Summoned monster has its effects negated as long as this card is equipped to it.
This is a good card to Special Summon monsters from your Graveyard, if you have a way to recycle or retrieve the discarded monster.
You can also use this card to Special Summon Normal Monsters such as Vorse Raider, Sabersaurus. You can always choose to discard higher level Effect monsters to do so.
If you are playing decks relating to Elemental HERO Neos, you can discard Neos and Special Summon another Hero monster from your graveyard which is lower level than Neos, and use O - Oversoul to bring back Neos to the field.
Gozuki to mill Il Blud from the Deck to the Graveyard. Activate Overdone Burial, you can discard 1 Red-Eyes Zombie Dragon from your hand to the Graveyard, Special Summon Il Blud to the Field and equip Overdone Burial to it. At this point, you will need Storm to destroy Overdone Burial and simultaneously destroy 1 or more of your opponent’s Spell/Trap (if you have set other Spell/Traps), Normal Summon Il Blud and use its effect to Special Summon Red Eyes Zombie Dragon from the Graveyard to the Field. At the end of this combo, you would have Gozuki, Il Blud, and Red Eyes Zombie Dragon on your Field, and ideally destroyed a good portion of your opponent’s backrow cards, and ready to enter your Battle Phase.
It only negates their effects while it's equipped to the monster. As such, it won't negate the effects of cards like Exiled Force that Tribute themselves as a cost or the effects of things like Sangan that activate in the Graveyard.