What happens when a creature with a powerful ability like "entering the battlefield" in Magic: The Gathering is summoned onto the battlefield?

When a creature with a powerful ability like "entering the battlefield" in Magic: The Gathering is summoned onto the battlefield, its ability is triggered and takes effect immediately. This ability can have various effects, such as dealing damage to other creatures or players, drawing cards, or gaining life points. It adds a strategic element to the game and can greatly impact the outcome of a match.