It’s been reported that dolphins have been observed engaging in what some researchers suggest could be a form of recreational drug use involving pufferfish toxins. 

Pufferfish contain a potent neurotoxin called tetrodotoxin, which can be deadly to humans if ingested in sufficient quantities. In small doses, however, it can induce a state of euphoria or intoxication. 

There have been anecdotal reports of dolphins apparently deliberately ingesting pufferfish and exhibiting unusual behavior afterward, such as swimming sluggishly or floating. 

It's worth noting that dolphins are known to be highly intelligent and curious animals, and they have been observed engaging in a wide range of complex behaviors. 

The idea of dolphins purposefully getting "high" on pufferfish toxins is certainly intriguing, but more research is needed to better understand this behavior.