The three Times Dipper was summoned and it didn't go as planned, for better or for worse.

First human sacrifice

Dipper Pines, also starting to be known as Alcor the Dreambender. Arrived in the circle with his customary, new, W͍͖̦͚̪̯͈̣͖͋͌̒̅́̍̔̀͒̚h̪͙̯̭̤̪̰͈̪͓̄̓͛͋͆̍o̳̬̘̣̮͗̀̄͗̈̉͒͑̽̃̇̐ D̞̭̙͖̩̜̽͌͆̌̇̌̓̇ͅa͍͖̰̫̤̎͊̐̂͑̿̎r̩͍̝͔͍̟̳̃̄̂́̔̓̐͊̓̅̌̚e̝̞͙̭̪̣̠̲͉͙̊̓̔̽̓̈̾́̉͛̚ṡ̫͚̟̥̥̜͈͕̩̎̓̚ͅ S̖̲̥̪̙̪̟͇̞̱͔̀͂̉̀̅̍̎͗̚u̠͈̰͙̗̠̘̩̽̀͆̆̚m̩̦̙̯͓̠̠̭͕̦̫͓̈́̒̊̆̒m̯̥̠͔̣̙͔̠̖̬͒̎͊͛̚ͅǒ̲͓̳̫͍̜̾͒́̅͗̊̒̽̚n̦̱̤̪͇͔̘͉͒̉̋͆̀͛̈́̃̊͒̚̚ͅ Ä̩̮̬̳̠͉̬̞́̓̑͂̿̀͐l͉̳̝̝̙̥̤̬̝̣̦͑̈̅̇͋̀̅́c͈͖̦̘̞̀͊́͆̾̽̚ö͍̬̜̪̝́̊̄̿͒̋̎ͅr͇̰̥̳̩̠̩͇̽͊̌͆ͅ Ț̠̪͔̬̖̖̤̩͈͍͗͆͒̊̏͊̊̅̍h̬̞͙̭̍̉̀̿͑̃̌e̱̟͚̝̟̎͛́̑̃̾̍͊ͅ D̟͉̫̱̄̀͋̆̽̆̌̀r̬͙̜̟̯̜̜̦͈͚̰̠̄̅̏̇e͚͔̠̯̮͉͗̌͂̓̍̈́ä͕̫̬͎̲̘̦͔̫́͗̊͐̿̊̔́̈m͈̳̩̟̰̮̩̝̅̎̉̎b̫̜͙̮͕̫̭̝͔̉̽̈̈̊́e̠̘̰̩̩̳̰̖̪͍̐͌̅̏̂̊ǹ̩̠̜͕̒̍̃̎̃͆͗̔̊̍d̝̥̖̱̅̏̒̏͛̅͂ĕ̤̫̳̝̬̳̦͆̂̇͂̂̂̓̐̒̃̑r̤̗̪͍̣̗̯̳̘͖͂̈̋̓ͅ? Only to see the cult.

And the P̠̤͍͎̣͕̱͖̯͔̳̱̈́͐͊̆̈͐̇̓͛̔̍̚ë̜͕̫̤̫͙̗͉͙́̑̐̀̉͛͂́́̋̚ȑ̯͖̬͔̞̪̫̲͈̯̜͇͗̀͊̆̄́͋̎̃̚s͕͖̯̟̦͕̑͋̉̂̍̓̈̋ȏ͉̗͙̖̞̩̥̍͊̈́̀̏͂̅̾̌͗̓n̝̜͖̦͇͓͎͂̃́̒̔̑͆̚ͅͅ bleeding out in the center of the circle. He screamed in a demonic crackle of rage.

His human half faded away and let he go of himself, forgetting Dipper and just being Alcor.

When he came back to himself he saw the humans in the floor, slaughtered, their blood drained by his own mouth, he fled the physical plane with a screech, back home to Mabel.

The one time they were all wearing crosses…?

Dipper was pulled away from violin lesson he was giving Hank (how dare they interrupt his time with his niblets) only to see, crosses? Lots and lots of crosses, including the people wearing them.

They are wearing them like masks, framing their faces, and they are also wearing them as costumes that strategically cover up certain area so you can't say they are showing more skin than appropriate. All in all, kinda weird. And they have these looks. Like a triumphant child, and he knows that face all too well from Acacia. "Yeah, whatdaya want?" He asks, adjusting himself in midair so he is sprawled comfortably. Judging by the looks on their faces the crosses were supposed to expel or at least harm him but all they do do is a slight ringing in his ears. He chuckles. As much as he wants to stick around and teach them a lesson, he has a violin lesson to get back to with Hank instead.

The one time they were all naked

He took one look at the naked cultists standing completely casually, albeit in classic cultist pose, and shot away with a demonic N̶̢̹͙͖̭̱͕̘̭̘̑ͅȏ̶̧̺̝͍͖͙̼̥̗̈̀͑̅́͐͜p̷̰̜̗͕̮̥͚̝̘̎͛̑̊̔̚͠ē̷͉͎̹̳̰͚̥̞̘̣̯̓̄!̴̨̤̩̗̗͇̩̏̃͋̑́̊͌̓ ̸̡̡̞̺͚̯͍̥̭̠̝̐͋̑̈́͐͛͂. He was NOT dealing with this today.