Cheapest priced copy (The List): $1.29 at Card Kingdom, near mint, their price list as of .
Thantis, the Warweaver 
Legendary Creature — Spider · 5/5 · Mythic · The List · #C18-46
Reach, vigilance
All creatures attack each combat if able.
Whenever a creature attacks you or a planeswalker you control, put a +1/+1 counter on Thantis.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
2 printings · $1.29 to $1.49 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander 2018 | 46 | Mythic | — | $1.49 |
| The List | C18-46 | Mythic | $1.29 | — |
3 rulings from Wizards of the Coast
- 13 July 2018If a creature can't attack for any reason (such as being tapped or having come under that player's control that turn), then it doesn't attack. If there's a cost associated with having it attack, the player isn't forced to pay that cost, so it doesn't have to attack in that case either.
- 13 July 2018Each creature's controller still chooses which player or planeswalker the creature attacks.
- 13 July 2018You can't attack yourself or your own planeswalkers to give Thantis +1/+1 counters, but Thantis appreciates the way you think.