Cybermat

Skulk (This creature can't be blocked by creatures with greater power.) Whenever this creature attacks and isn't blocked, it gets +X/+0 until end of turn, where X is the number of attacking artifact creatures.

From Magic: The Gathering.

Open the interactive version on https://mythscribe.cloud/app/tcg/cards/cms6o2coz0f9dpb1hiyrz8c18.