One day some neighbor kids were playing outside the window, and my sisters were shouting out that we'd come out and join them. Horrible creatures then pounced into the area - vaguely conical with two thick legs. Their whole front ends were a gaping maw of inward-facing fangs - and the entire front half of their bodies telescoped out so they could latch their maws on victims.
The neighbor kids giggled as they trundled up, and i shouted "stay away from them! stay away!" but they were fascinated. "What are they?", they asked, laughing and poking them sticks. "They're cryptids, we don't know if their dangerous or not, stay away." I tried to climb out the window to stop them, but it was too late.
Then, predictably, the Cryptids swallowed the kids whole. They then excreted the kids, who had been converted into Cryptid larvae, only they looked like the kids. The kids then went home and infiltrated their families. Then weird dream-shift happened. My whole family had been converted, as had other friends and people. But I knew MJ was still safe, so I determined to save her. I pretended not to realize what was going on, even as I tried to acquire some kind of weapon. I had to play a weird game of seeming to go about my casual, every-day business while actually scrambling for a gun or something. It was nerve-wracking. I finally made my move - I burst out of my room and a couple of the first stage Cryptids, the conical things, were there. I fired at them, and they died, but I was out of ammo. Then the human changeling-cryptids keened in sorrow that their "parents" had died, and they locked me up. I tried to fight but I was overwhelmed.
They locked me in my room. I had to get out, to save MJ, but i couldn't. Finally I decided that if I couldn't rescue her, I could at least keep her safe one way. I found a can of gasoline in my closet (don't ask) and poured it all over my room. I got a lighter, and then shouted for the Cryptids to come talk to me. I told them I wouldn't negotiate until they were all there, so I could explain it to the lot of them.
They filed in, some first stage, some human-changeling cryptids. When they were there, I started to really get up on a soap-box and speechify, all about just as they suffered when their families were hurt, so were they causing us to suffer. Some of them started to look remorseful, and some others filed in to hear what i was saying. Then I lit a lighter and set the bedspread on fire.
They tackled me, and one of them put the fire out. But my hand, under the dogpile, was still free so I lit the fire again, and then in another place - I wanted the whole place to go up. Only the flames wouldn't spread fast enough, and they kept putting it out. But neither did they just take the lighter away either. I tried to blather at them, to get them to stop paying attention to the lighter, but it didn't work.