Pokémon Go has a cheeky Grass and Gratitude event for 4/20

Roll up, roll up, Pokémon Go's latest in-game event begins today, 20th April - and fans think it contains a cheeky nod to 4/20.

Today brings the long-awaited free release of Grass-type Mythical Pokémon Shaymin - for those who didn't cough up for a paid Go Fest ticket last summer.

Sparking up players' attention is the title of this event's new Special Research questline - "Grass and Gratitude" - which is available now alongside the game's similarly grass-themed Sustainability Week.

It's the second year in a row Pokémon Go developer Niantic has held a Sustainability Weed event - sorry, Week event - over 4/20. Last year's celebrations saw the debut of Grass-type Pokémon Cherubi's Shiny version. That Pokémon's number in the franchise's official Pokédex? #420.

Perhaps this is all smoke and no fire? But to be blunt, some fans now believe references to 4/20 are now high on the agenda, and something of a regular joint.

For more on Pokémon Go's Grass and Gratitude research, check out Eurogamer's guide.