Likely clover mite

Common around building foundations, windows, patios, and vegetation, especially in sunny, dry areas.

Feeds primarily by piercing and sucking sap from grasses, clover, and other plants; it does not bite people or pets.

Often gathers in dense patches and may enter buildings through cracks. When crushed, it can leave a red stain; populations are commonly highest in spring and fall.

Harmless to humans, pets, and structures, though large numbers can be a nuisance and may discolor surfaces. Usually causes little meaningful plant damage.