Thantis, the Warweaver 
Legendary Creature — Spider
Vigilance, reach All creatures attack each combat if able. Whenever a creature attacks you or a planeswalker you control, put a +1/+1 counter on Thantis.
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyLEGALvintageLEGALcommanderLEGAL