Cheapest priced copy (Teenage Mutant Ninja Turtles Source Material): $3.49 at Card Kingdom, near mint, their price list as of .
Leo's Katana 
Sword of Sinew and Steel
Artifact — Equipment · Mythic · Teenage Mutant Ninja Turtles Source Material · #18
Equipped creature gets +2/+2 and has protection from black and from red.
Whenever equipped creature deals combat damage to a player, destroy up to one target planeswalker and up to one target artifact.
Equip {2}
Legal inCommanderModernLegacyVintage
Not legal inBrawlStandardPioneerPauper
3 printings · $3.49 to $19.99 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Modern Horizons 1 Timeshifts | 31 | Mythic | — | $11.99 |
| Modern Horizons | 228 | Mythic | $9.49 | $19.99 |
| Teenage Mutant Ninja Turtles Source Material (Leo's Katana) | 18 | Mythic | $3.49 | $4.99 |
One ruling from Wizards of the Coast
- 14 June 2019Protection from a color means that the equipped creature can't be blocked by creatures of that color, can't be the target of spells of that color or abilities from sources of that color, can't be enchanted or equipped by Auras or Equipment of that color, and all damage that sources of that color would deal to it is prevented. Nothing other than these events is prevented or illegal.