|Would you like the sword+1 or the sword+1|
Hmmm…according to the mage in your party it has a strong transmutation enchantment. The blade is anvil forged and crafted from fine (maybe rare) alloys. The handle is wire wrapped and the cross guard and pommel have strange runes on them. Surely this obviously magic sword must be AT LEAST +1???
WRONG. That sword you have unearthed is actually a sword+0! This very rare weapon enchants itself when it deals a successful hit against anything magical. This could be a creature, obstacle or a static spell. The sword gains a cumulative +1 for every five levels of the target. This requires DM adjudication based on the rules and game system being used. The sword +0 always counts as a magic weapon for determining a hit and damage even before it steals any pluses. Any pluses stolen are temporary and last only 24 hours.
Go ahead…brag about your sword +0 because it sure is better than that sword+1 you just found.