Lavamancer's Skill is a common Enchantment — Aura card from Onslaught (ONS), collector number 215. Current market price: $0.17 (foil $0.93), TCGplayer market prices via Scryfall.
Enchant creature Enchanted creature has "{T}: This creature deals 1 damage to target creature." As long as enchanted creature is a Wizard, it has "{T}: This creature deals 2 damage to target creature."