Timbermare is a rare Creature — Elemental Horse card from Planar Chaos (PLC), collector number 140. Current market price: $0.34 (foil $5.50), TCGplayer market prices via Scryfall.
Haste Echo {5}{G} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.) When this creature enters, tap all other creatures.