What occurs when the 'gets +1/+1' part of the Wild Mongrel effect is applied?

The application of the 'gets +1/+1' effect of Wild Mongrel occurs in Layer 7c. This layer is specifically used for effects that modify the power and toughness of creatures without using counters. When you activate the ability to give Wild Mongrel +1/+1, it represents an effect that changes the base characteristics of the creature temporarily, falling into this layer.

Layer 7c is designated for effects that modify a creature's power and toughness, and since Wild Mongrel's ability grants an immediate (if temporary) increase, it fits perfectly into this category. In this layer, effects that are known as "static" or "temporary" modifications to a creature’s stats are handled, ensuring that they reflect both the current game state and the interactions with any other active effects in the game.

Understanding the specific layers is crucial in Magic: The Gathering, as it helps to resolve interactions among various abilities, effects, and modifications accurately.